[SpicyLemonZest]

Many states do operate tuition-free programs for residents at their public colleges. But students with good grades often prefer to take a large amount of debt rather than go to the local state school, and it's not clear how you would go about changing that.

[penguin1029]

This. If you want education to be cheaper or free, you'll need to give up some amount of choice.

Most states in the US already have public university systems, but that isn't where most of the debt comes from.

Everyone wants to go to Harvard, Stanford, Princeton, etc.