While what you're saying is true, the fact is, nothing else is safe to that extent. You know buildings are not even that sturdy.
What I mean is, they have a good chance of collapsing even without an earthquake. Good, meaning more than if you had a backup with a back up with a backup... x times. I don't know what this x is, and it's probably different for different types of buildings, but this x is significantly less than infinity.
What I'm trying to say is, there's a risk to everything, and if you can't accept even such a small risk, there really isn't anything you can do.
There are many more things people do that are much less sustainable. Excessive use of natural gas, for example.