This is a particularly pernicious misunderstanding because it leads people to believe that they have to take out loans to go to college or they will earn less money. Saying "People who do X make more money" can have consequences if that statement isn't necessarily true.

What you want is a study that shows that people from lower income quintiles that go to college have a higher lifetime earning than people from the same quintile that didn't go to college. Maybe that exists? if it did, I'd imagine the pro college people would be waving it around everywhere.

Using Google Scholar to find relevant research is a great habit. but you really have to read it to make sure it says what you think it says