It's good that your major allowed you to finish in 3 years, but many majors require 4 years because of the way the clbuttes are ordered, and prerequisites aren't always offered over the summer-winter breaks.
You picked a plan that worked well for you, but some people like the job experience they can get by working through college. When I was in college I was managing a pooty taco shop for pooty pay, but I learned a ton of lessons at that job that college never could have taught me.
There's other benefits to working through college, such as having good refrences from those employers once you're applying for a "real" job. Not paying back those debts isn't a bad thing, since it's less out of pocket money once you have a real job.
That, and it worked out well for me when I decided not to finish college that at least I had a few jobs and good references to prove my worth when looking for a long-term job.
Of course, since I've done fine without college I could make the argument that it's always a waste of money. I know that's not true though, there is no right or wrong path to take through life, just some really stupid ones.
Dave