FYI this actually happened: http://venturebeat.com/2010/03/03/life-investment/
If it worked like you described, I'd expect a break from the IRS since my education mostly took place elsewhere, and I'd still be writing checks to the Canadian government for the education and healthcare I got as a child. (That wouldn't necessarily be a bad thing, but it's not how it works.)
From the government's perspective, they make a blanket investment in everybody in the form of providing education and services. Some people end up paying huge amounts back in taxes, others pay nothing back.