LAS VEGAS -- Given a chance to put the narrative that has surrounded them for most of the past five years to rest, the San Francisco 49ers instead funneled all of it into a much larger question after losing to the Kansas City Chiefs on Sunday in Super Bowl LVIII:

If not now, when?

These battle-tested and scarred Niners were built to win the franchise's long-awaited sixth Lombardi Trophy, and they made bold moves over the past two years to do it. They traded four draft picks for running back Christian McCaffrey. They gave $40 million guaranteed to tackle Javon Hargrave to help plug a hole in the middle of their defense. And they found and developed 2022 seventh-round pick Brock Purdy, whom they steadfastly believe is their long-term answer at quarterback.

Even the travails of the past four years -- a blown 10-point fourth-quarter lead to Kansas City in Super Bowl LIV, an injury-ravaged 6-10 pandemic season and back-to-back disappointing losses in the NFC Championship Game -- were seen inside the walls of the Niners' facility as fuel to strengthen their resolve.

Instead, the Chiefs stamped themselves as the league's newest dynasty with a 25-22 overtime win for their third Super Bowl title in five seasons, with the Niners on the miserable end of two of them.

Sunday's loss added one more devastating defeat to San Francisco's ever-growing pile of them with seasons and championships on the line. Ray-Ray McCloud III's muffed punt, Jake Moody's blocked extra point and Patrick Mahomes' late-game heroics sent the Niners into another offseason with the saltiest of tastes in their mouths.

Those moments join Michael Crabtree in the corner of the end zone in Super Bowl XLVIII and Tyreek Hill's 44-yard catch in the waning moments of Super Bowl LIV as the indelible images of championships that got away.

"Yeah, I was speechless. Couldn't really look anybody in the eye. Especially all my teammates," defensive end Nick Bosa said. "I could have done more. Everybody could have done more and there's really not much to say at this point. It's going to hurt, it's going to hit in waves, but that's life."

The number of years without a title now sits at 29, a shocking amount of time for a franchise that racked up five Lombardi Trophies in a 13-year span from 1981 to '94, led by some of the greatest players and coaches the sport has known. San Francisco is the fifth team in league history to lose three straight Super Bowls, a streak that follows it winning in its first five appearances in the big game.

And now the Niners must contend with the present failure and the unknown of the future. The championship window for the roster's veterans might be shrinking ahead of a looming 2025 payday for Purdy.

"The hardest thing is looking at the guys, the Ronnie Lotts, the Steve Youngs, the Joe Montanas, when we haven't done that," general manager John Lynch said. "Because those guys have had our backs, and we want to have theirs and so they know we're fighting, but you got to pay that off.

"If you want to be great, that's what you've got to do. You've got to bust through."

IN THE AFTERMATH of this loss, plenty of attention will be paid to coach Kyle Shanahan, who has been on the losing side of the only two Super Bowls to go to overtime. He has completed his seventh season as an NFL head coach and, at 44, has plenty of time to finish the job.

But it's difficult to even get to the door of the Super Bowl, let alone to kick it down and walk away with the Lombardi Trophy. Before Shanahan got the 49ers to a pair of Super Bowls in a four-year span, Jim Harbaugh restored San Francisco to contender status.

From 2011 to '13, Harbaugh led the Niners to the NFC Championship Game every season, including their first since 1997. In his second season, they reached their first Super Bowl since 1994.

Despite getting so close so often in four seasons in San Francisco -- he left for the University of Michigan after the 2014 season -- Harbaugh was unable to break through.

"There's no other sport as competitive as the National Football League," Harbaugh said last week. "I dream about having another crack at it."

What's harder to accept is how challenging it is to break through when Superman is wearing the other team's jersey. For many years, it was Montana who helped prevent Hall of Famers such as Dan Marino from getting a ring. Tom Brady's dominance over two decades kept other greats such as Aaron Rodgers and Drew Brees from having more than a solitary Super Bowl title.

We're now in the Patrick Mahomes era, where teams have to go through Kansas City and its stellar quarterback to win a championship. It's one thing to have Super Bowl talent, but sometimes a team can be great at a bad time.

All of which makes this latest loss even harder for the Niners. They're 0-4 against the Chiefs under Shanahan, with three of those losses coming by double digits. It's the most losses without a win that San Francisco has had against any opponent under Shanahan. Even if the Niners get back to this point, there's a real chance that Mahomes, Andy Reid & Co. will be waiting.

"This is my second (Super Bowl) as the head coach, but I think when you go against guys like Tom Brady and Pat Mahomes, you better never feel comfortable with the lead," Shanahan said after Sunday's loss. "Those are two of the best players to ever play the game. That's why when you have a lead or you're down points, those guys are always in it. You watch 'em all the time do that stuff."

Before Sunday night's loss, the Shanahan and Reid comparisons were already being made. Reid went to five NFC Championship Games and a Super Bowl in his 14 years as Philadelphia Eagles coach, then made five playoff appearances and an AFC Championship Game in his first six seasons with the Chiefs before getting his title in Super Bowl LIV.

The label that came with that was "best coach to never win a Super Bowl." The importance of getting over the hump isn't lost on those in Shanahan's orbit.

San Francisco cornerback Charvarius Ward was with Kansas City when Reid won his first title. While he believes Shanahan is already on the same level as his former coach, he knows how much Shanahan wants to win it all.

"[Shanahan] eats, sleeps and breathes football, too," Ward said earlier this week. "I think that's going to solidify everything for him in his career, getting that Super Bowl ring. I feel like that's the only thing he's missing. ... Everybody knows he's one of the best minds in football."

But the scars from these losses have a cumulative effect. Shanahan has said he usually needs at least a month after the season to clear his mind and be ready to get back after it, especially following season-ending heartbreak.

It's a feeling Harbaugh can relate to. Even now, 11 years after losing to the Baltimore Ravens in Super Bowl XLVII, the wounds remain.

"I think about it every day," said Harbaugh, who is back in the NFL after he was hired as the coach of the Los Angeles Chargers in January. "What could we have done differently at the end? How could we get the ball in from the 5-yard line?

"It's vivid, and you walk off that field going, 'There'll be other days,' but that might've been the only day."

AS THE 49ERS trudge into another offseason, Shanahan will have little time to grieve. He and Lynch have to figure out what they can do to shed the also-ran label.

The 2023 Niners will go down as one of the most talented teams in franchise history. But without a Super Bowl title, they're in a tricky spot. While they have most of their biggest stars under contract for next season, the 49ers are $43.96 million over next year's projected salary cap, according to ESPN's Roster Management System. And 2024 figures to be their last season with Purdy playing for peanuts on his rookie deal.

In 2025, Purdy will be eligible for an extension that likely will multiply his 2024 cap charge of $1.12 million up to 50 times over. That could mean the Niners have to make difficult decisions on some of their high-priced veterans. It's why, entering the 2023 season, logic suggests this could be a two-year window to win the Super Bowl, at least with the current core of veterans. York scoffs at the notion.

"When you talk about windows, I just think that that's such a B.S. concept in this league," York said. "You never know when you're going to have the opportunity to be here. You have to make the most of it."

Still, some of that veteran core, such as seventh-year tight end George Kittle (two receptions for 4 yards on Sunday), have acknowledged the idea of a window and have made it clear that they need to break through it as soon as possible.

Among the team's top offseason priorities will be signing emerging star wideout Brandon Aiyuk (three receptions for 49 yards), who is entering the final season of his rookie contract, to a lucrative extension, but the Niners also have to plan for the future while trying to make moves to win a championship next season. They'll need to take a long look at their defense, where they've invested big money in a line that hasn't been as dominant as hoped, an offensive line that -- minus 35-year-old All-Pro left tackle Trent Williams -- has often struggled, and begin planning for the future in the secondary.

"We've been so close so many times that it's only so many more opportunities that we have," Bosa said on Sunday. "We have amazing core of players that are going to be back and we have to be better."

On Monday, as the 49ers took their 40-minute bus ride from their Henderson, Nevada, hotel to Allegiant Stadium for the NFL's opening night media event, Bosa and linebacker Fred Warner reminisced on their journey back to the Super Bowl.

At one point, they compared notes on how many members of their respective draft classes remained on the roster. Warner realized that in five years, every other player drafted with him is gone. Bosa had pride in the fact that, four years later, he had three draft classmates left.

The two biggest stars on the 49ers' defense came to the same realization: One way or another, sweeping change comes for every team. It's especially true for a team that, after trying to run it back with the same core, might need a more aggressive upheaval to push it over the finish line.

"We have the team obviously to do it, to win the whole thing and come up short like that. [That's] the way things have been the last couple of years here," Purdy said. "Everyone wanted it so bad. So I think we're still trying to sort of gather our thoughts and everything right now, but everyone in the locker loves each other. I'll tell you that."