Yeah, the language factor is hugely underrated.
I think it's less the money aspect, and more the fact that American society is more bland, uniform. It's easier to fit in. In Europe, unless it's a true international metro (amsterdam, london, brussels, ...), there's a huge cultural barrier. You just can't hitch into it as an adult. Your children will fit in, but not you.
But plenty of them find it hard to fit in socially, and then leave later.