Too much money is at stake (advertisers, networks, etc) for the Olympics to be postponed, but if they move it, I wonder if there is anywhere in the world that could be ready to host it at that time. London deconstructed much of their infrastructure, so they're out. Beijing perhaps? Honestly, Los Angeles could probably handle it by housing the athletes at UCLA and USC and expanding the geographic range of events down to San Diego and up towards Santa Barbara.
Moving it seems like a mammoth task. Think of all the flight & hotel bookings that would change. The disruption it would cause makes it near impossible that it will be changed now, I think.
I don't mean to suggest that it wouldn't be worth cancelling or changing if the health risk is so big, just that (like with climate change), humans have a disorder when it comes to this sort of thing.
Oh, I'm not suggesting it would be easy. The logistics alone make it near impossible, as the hotels and airlines would need to be comped. I was speaking specifically about whether or not it would even be feasible to move it based solely on having a location that has the infrastructure to support it.