The difference is even more pronounced in places where tertiary education is subsidised. For instance in Australia there is a system to reduce the cost of uni education for most local students.
Those that don't quite get in can pay full fees (like international students do) for slightly reduced course entry requirements.
That said, I was a) lucky enough that my parents were willing to pay for my uni education for me, which not only lead to no hecs debt, but also a discount on hecs; and b) I went to a selective high school, and thus I only know a couple of people from my high school who didn't at least start uni, if not finish it so my sample may not be so accurate.
Not only does having a degree typically result in higher pay, in many jobs these days having a relevant degree is pretty much a requirement, if not a relevant degree and at least 1 year's work experience. None of my friends who have finished their degree and not gone onto further study has had difficulty finding work. The only one that has had trouble was the one that dropped out of university.