Maybe a contributing factor is that it is significantly easier and more acceptable to move house in America. Thinking back to where I grew up, the house we lived in was where my grand-grand-parents were born; it would be pretty much unthinkable to move (and was not even possible in previous non-capitalist regimes) so people stick around in close-knit communities. But maybe if moving was dead-easy like in the States this would naturally fall apart?

I guess it's already happening to some extent with Schengen and young talented engineers moving to job centers.