>People vote with their feet. This shouldn't be a negative. Some people don't want to be over taxed and over regulated in places like CA and NY, so they move to states they see as fitting their needs/culture better.

Sure but the point being that that would incur an exit tax from most major countries, whereas the freedom of movement within the US creates this weird system where you can gain incredible wealth benefitting from the infrastructure and economy of one state, then just walk away and decide not to be taxed any longer. I'm not saying it's a bad thing, just that that ends up screwing over the state in the long term.