The Bay Area is saturated with sports venues, with a brand-new Downtown basketball arena opening next year and the 49ers' new home, Levi’s Stadium, only a year old, the new venue construction in San Francisco wouldn't be nearly on the scale other cities require. It's likely that Oakland, San Francisco, and Sacramento all will have NBA venues still standing then. The waters around San Francisco Bay are perfect for sailing, but not far up the road in Sacramento, Lake Natoma and the Sacramento River offer calmer waters for rowing and other water events.
The sticking point in the city's attempt at the 2016 Olympics came down to the lack of a site for an Olympic Stadium. On a tightly packed peninsula with zillion-dollar rents, where to erect that keystone venue, and what to do with it afterward, would likely be the greatest hurdle a decade from now. (Though it's pretty much guaranteed the A's will still need a stadium then.)
That challenge, though, as well as the greater question of expenses, does offer the city a chance to shape its identity for the next century. But as Texas has energy money, NorCal has tech money. Will these companies pony up to put their names on Olympic venues? Can they all pull in the same direction long enough to lead the world in something beyond seed rounds and futurism? The Olympics have a strange power, on this count, to pull people together. A unified San Francisco Bay Area would be a marvel to behold.