In the middle of XX century, small-to-medium sized cities looked like an attractive place. That was unprecedented before and it doesn't look like it's going to repeat.
I think we will live a revival of these places, they provide better quality of life in many aspects, and can be very interesting for people who are fed up with the big city.
People who are fed up with the big city will much more likely prefer mountains or tropical islands or deep lakes, something that most of small-to-medium cities built around an university and a factory just don't have.
Also, in the big city people get used to theatres and museums and events. Smaller cities just don't have the density.
