People don't make decisions in a vacuum. I don't get to choose where I want to live based solely on what I enjoy. A big part of what keeps people in a city is the network effect; cities are where the jobs are, so the people have to live there, which makes companies want to move to where the employees are, which makes people live there.....

Plus, you have families, cost of moving, home ownership, etc, that keeps you in a place even if you might enjoy living somehwere else more.