I don't see this as something just for the very rich. Citizenship is less of a big deal for Americans because they're so geographically isolated, but elsewhere, people cross national borders very often indeed. (Compare it to how often you cross state lines.)

Wealth has very little to do with it globally, at least beyond a certain value. It's to do with mobility of assets, of yourself, and of the people and things you care about.

I'm actually pretty convinced that borders and nations as we know them are another example of a bottleneck that is ripe for innovation by a new model - think of AirBNB or GetAround as tiny little proofs of concept for a much bigger possibility.