Thats very true in a way. A while back, just for the heck of it, I looked into a success rates of for profit colleges. They were absolutely terrible. Then I discovered that the success rates of older students attending traditional colleges were also terrible. On the surface this seems to go against what you are saying, but I kept digging, and I found a study that compared younger and older students college performance on the bases of equalizing their high school academic performance and SAT scores. Turns out, most older college students were terrible students in high school (probably explains why many of them didn't attend college directly out of high school). But when well academically qualified older students were compared to traditional college age students with equal qualifications, the older students almost always did better.
I have an acquantance, the parent of a kid who my son went to school with, who went to college at age 40. He graduated last spring, it was just our local community college, but he had a 4.0 gpa and was the only graduating student with a 4.0.
Personally, I attended college for two years, then did some time in the military before returning to college. I did much better after my stint in the military, I studied more, never missed a class, and it paid off with better grades.
I am all for highly motivated well qualified students who know exactly what they want to study in college going directly into college from high school, but many people would probably better off waiting a few years.
