They were arguably never placed in fact never placed in the culture. There are 24 hours in a day. In what culture does one spend most of those hours?
Imagine if those same people would have been adopted as newborns, by a rural family on a farm in Belgium, France or Germany.
This isn't inherent to Europe, nor to any particular background. I live in Korea. Most Western immigrants here spend most of their time not inside the culture. They both work and relax outside of the dominant culture. If they have children here, and raise them similarly, those children will also have different values. But if they put their child in environments where everyone else is from the dominant culture, for >8 hours per day ever since kindergarten, then that's the values they'll take on.
It all does come down to culture. For what it's worth, I'm originally from Europe, and very familiar with the phenomenon you're talking about.
Someone else here rightly mentioned the internet as changing this somewhat, which has some truth in it - it does affect the probability distribution. But by and large, it still holds.