I can't comment on Europe simply because I haven't lived there, but in my experience the US isn't at all like you mention. Sure, there might be states where people are willing to move, but if you think of cultural regions more and states less, people never leave certain areas their entire lives. I'm talking about areas like PNW, New England, Upper Midwest, Southern states and so on. This is very similar to your case, it is just that the US is far more fragmented in some sense, and some states can be similar to others.