LOS ANGELES — By 2028, a new stadium being built for the Rams and the Chargers will have been beaten up by nearly a decade of NFL games. The seemingly intractable problems of southern California – traffic and homelessness – might get better or grow worse.

So much can change in 11 years.

Los Angeles’ decision to lock in an Olympic Games to far-off 2028 was praised by city leaders Monday as a deal that offers hundreds of millions of dollars in future benefits. But the longest wait time for any Olympics in the U.S. also comes with the risks of the unknown.

“It’s a big chunk of time,” said Jules Boykoff, a Pacific University professor who has written widely on the Olympics. “You just don’t know what’s going to come. The world presents surprises.”

History teaches that the economy swings up and down, sometimes with disastrous results. Political scientists foresee an era of continuing upheaval and unrest. Geologists say an inevitable big earthquake in quake-prone southern California could damage venues envisioned as part of the Games.

Mayor Eric Garcetti shrugged off a question about the uncertainty.

“Los Angeles is resilient,” said the youthful-looking mayor, who will be granddad age, chasing 60, by the time of the Games.

“If the entire earth falls apart, probably the Olympics aren’t happening in Los Angeles. But short of that, we are going to have a great Games here in LA.”

In embracing the 2028 date that’s expected to be finalized later this year, city Olympic organizers ceded the 2024 Games to Paris, which both cities had craved.

But Garcetti and other supporters argued that the four-year delay was advantageous, giving the car-choked city more time to build rail lines.

Additionally, the delay comes with financial sweeteners that, among other things, will pump millions of dollars into youth sports.

But time rushes on and much will change.

Los Angeles County is home to 10 million people, and that population could increase by more than 500,000 by 2028, state demographers project. The cutting-edge technology in the new NFL stadium, now scheduled to open in 2020, will probably look like the forgotten Blackberry by 2028.

Many athletes in their prime today will be in the bleachers in a decade. And how can officials accurately estimate ticket prices and the revenue they will generate?

Events that happened 11 years ago can seem part of a faded, distant past. Facebook was a mere two years old. Iraqi dictator Saddam Hussein was executed. Taylor Swift released her first album, and “Game of Thrones” was years into the future.