[Paul11]

Generally, young people are more prone to change and allowing new ideas to permeate their psychology. There are always exceptions to the rule, such as your examples. The ones who "get it" and can nail themselves in are the minority. By far, most folks can only live there for so long without at least going home for long breaks.
Also, most people are there because they enjoy it. but we all knew people who couldn't come back. Certain prime years slip by, a few years puts one behind the times in their own countries and they feel like it's almost impossible to leave. we've all met them.