They might be related, though. The ruling class has deliberately destroyed local communities and forced people to become an on-demand proletariat that will move (often at personal expense!) "where the jobs are". If you want to have a career in tech, for example, you pretty much to live in one of 5 or 6 highly expensive cities, because you won't be taken seriously if you live anywhere else. It's not necessarily pathological that Americans move so much; what is pathological is that they have to do so, just to survive.