I'm reading about those California cities going bankrupt and everyone seems to think that this is something new. Oh, no, my child. Cities have been going bankrupt since mankind bound together to live in cities. Poor fiscal management, an imploding economy, lack of jobs, declining housing market, all these things conspire to make people move away. Sometimes it's a trickle, sometimes it's a flood, but folks have been building and abandoning cities since time immemorial. Remember studying Troy? Point at it on a map.
More recently, in the late 19th, early 20th century we made a lot of boom towns here in the US, then abandoned them. Google "ghost town" and see how many hits you get. Wikipedia is a great asset when you want to talk about ghost towns. Folks move in, folks move away. After a while, it just doesn't make any sense to stay in that spot, so we pull up stakes and go where the opportunity is. It's the American way.
This ain't nothing new, folks. It's as American as apple pie.