Missing from the 'great replacement' argument is the simple fact that population churn is one of the leading factors for creating a broken, consumption addicted population.
People live normal, well rounded lives when they belong to a healthy functional extended family and community. Children instinctually get a healthy identity, and people feel a purpose and reason for existing.
When this balance is upset, people withdraw to comfort: watching tv, streaming, consuming. They lose contact with the outside world in a physical, social and spiritual sense.
Parents who spend 18 years diligently shielding their kids from the rotten broader culture won't even blink about sending those kids off to a far away university. Those kids will be removed from a source of strength at just about the worst possible time.
The loss of a rooted nature begets a whole host of broken social afflictions. Kids and young people look for a reason for existence, or identity, usually leading to listless and broken people online. Groomers have an ample supply of lost wandering kids.