Better San Fran than Boston. Boston really *doesn’t* have room to build venues. If there was a way to use existing sites for the events, it might work, but even then, traffic would be an absolute nightmare.
On the other hand, it would be kind of neat to see the rowing events held in the Charles Basin, and the marathon can use the traditional Boston Marathon route, which is one of the better world-class routes.
I don’t think they could use the Boston route. I think the Olympic rules now require a point to point marathon, beginning and ending in a stadium. (better to sell tickets)