The assumption being that it's the government's job to invest in individuals. I'm not here to argue either way, but at least half the country would disagree that it is.
Why is the government involved in teaching children how to read, write, do arithmetic, and sit in a chair for 8 hours a day, then?
Absolute ideological opposition to government involvement in education - period - is a fringe opinion, that is at best, shared by ~5% of the country - not 50%. (Much of the 50% disagrees about the curriculum, but that's another story.)
For every example you give of a successful college dropout, I can give an example of a successful person who only forced themselves to slog through 12 years of schooling for the sake of social signaling, and not running afoul of truancy laws.