I strongly disagree. Most classes are pathetically slow and boring, not to mention expensive and time consuming. For one example, I've learned more history just reading books on my own than I ever did in History class, and it's not like I got bad grades back when I was in school. Showing up and being "carried along" was basically worthless.
It's likely that there are some kinds of classes that are functionally better than learning on your own, but given that the vast majority of classes on most topics are de facto going to be aimed at the lowest common denominator, you're gonna have to put in a lot of work to find good ones.
If you want to do history seriously, I think it makes sense to do it in academia. It's too easy to go off the rails otherwise.
More generally, there are two kinds of things we want to learn:
1) Purely intellectual areas, like math or programming. LWers have a comparative advantage here. But the uncomfortable truth is that most people who succeed in those areas had lots of schooling. (For example, Linus has a master's in CS, Google came out of a PhD project, and the idea of AI risk originated from academics like I.J. Good and Nick Bostrom.)
2) Areas with a phy...
LW has a problem. Openly or covertly, many posts here promote the idea that a rational person ought to be able to self-improve on their own. Some of it comes from Eliezer's refusal to attend college (and Luke dropping out of his bachelors, etc). Some of it comes from our concept of rationality, that all agents can be approximated as perfect utility maximizers with a bunch of nonessential bugs. Some of it is due to our psychological makeup and introversion. Some of it comes from trying to tackle hard problems that aren't well understood anywhere else. And some of it is just the plain old meme of heroism and forging your own way.