Not all of us could afford to attend a four year college directly after high school so I went to a junior college even though I had good grades in HS. I had to pay for college myself and not once did anyone offer to pay anything towards my education. Working two part-time jobs while going to school full-time, buying used books, and scrimping and saving at every opportunity led to a bachelors degree in four years. It was a character builder for sure but I only did what I had to do.
Closer to home. 18 year-olds are not always ready to leave.
As for 2 year technical certificates a trimester system would work best. Get to work sooner.
4 year institutions allow for a graduate to walk around with their nose in the air around the others.
I spent two years at community college and transferred to a four year university. Saved lots of money and had my loans paid off in just a few years.