I think they mostly do lack that insight, but it's not their fault. They've been taught from a very young age what the "right" path to adulthood is. It's hard to overcome that programming, especially since (US) K-12 schools aren't exactly about teaching creative, independent thought. People who come away from K-12 schools with that kind of thing usually arrived at it outside school.

(Also I think the parent meant that the 20-year-old would take $50k from their parents, not $200k. But agree that $50k is likely out of reach for most people in that situation as well.)