That makes perfect sense. I'm guessing people rarely drop out by choice. If you run into problems that prevent you from completing your degree, those problems probably aren't going to disappear just because you drop out, so it'll also affect your ability to work as well, and thus also your earning potential. As long as the prevalence of these issues is relatively small in the population, it'll get drowned out by everyone else in the no uni groups.

This is something important everyone forgets, the majority of those "self-made" billionaires started out as multi-millionaires.

There's also a difference between dropping out of university because you have an idea you have to dedicate all your time to right now or someone else may beat you to it and dropping out to manage a Wendy's or hawk "the new big thing"