School isn’t just learning the stuff in the classes. It’s the shared experience too. It’s the teachers holding you accountable for learning.
“Going to school” is a very different thing than just trying to learn on your own. Self motivation and time are a huge barrier for a lot of people. I think the OP was imagining being able to go to school every day and just take classes for free with other people also interested.
There’s a part of a highway near Denver where it’ll tell you to take a “slight right to stay on highway”, and there is literally no possible turn or off ramp there.