2. We're also actively giving them less paths in life to begin with. How many high school grads @ 18 will find any job whatsoever without additional school/training, and how else will they afford housing with zero income? The military is the only consistent employer at that age, and the only one who'd provide shelter with the deal.
3. On top of all that, it's in university's best interests to keep 1) and 2) the way they are. Their incentives start at recruitment, and end at enrollment. Past keeping them in college for 4-6 years, they do not care about performance, post-grad job placement, nor societal wellbeing. And part of that is due to a lack of pressure in the recruitment stage to make universities focus on such metrics. Turns out a fancy new gym is a cheaper investment.