Or you want someone to give you feedback on your homework and answer your questions (and hence a chance to clear up your misconceptions)
I mentioned Physics Forums for math and physics, where you'd get all the feedback you could ever desire.
or you want hands-on experience with lab equipment
Valid point.
or you want to socialize with other people interested in the same things
Why would you need college for that? If you keep procrastinating about getting out there and trying to meet people, college is a good way to self-bind oneself into feeling an obligation to show up somewhere on a regular basis that may lead to success in that area. But otherwise you could find people elsewhere.
or you want to be able to legally access papers behind a paywall for free
Another valid point.
Overall though, I wouldn't say you contradicted anything in my post. I absolutely did not say that going to college wouldn't be a useful endeavor for plenty of people. It's just that the reasons to go certainly have nothing to do with the quality of instruction or something like that, which is what the OP was about.
I mentioned Physics Forums for math and physics, where you'd get all the feedback you could ever desire.
Communicating in meatspace with people I know personally is much more effective than over the Internet with strangers, all other things being equal (at least for me -- YMMV).
But otherwise you could find people elsewhere.
Like where? Not only would I have no idea where to find half a dozen physicists hanging out together in my home town, I'm not even sure there are that many physicists at all there.
...It's just that the reasons to go certainly have
Compared to many of the people reading this, I've not participated extensively on LessWrong. In fact, I created my account only about a week ago. That said, I have read many LessWrong articles by contributors such as Eliezer, Jonah, Yvain, Gwern, and many others (if I missed you, my apologies). I wouldn't say it was a huge transformative experience. But I have probably learned a bit more from LessWrong than I learned sitting in on a class by Nobel Prize-winning economist Gary Becker on human capital (without formally registering for the class or doing the coursework). I've learned more of value from LessWrong than all the MIT OpenCourseWare lectures I've consumed. There are a few online experiences, such as reading EconLog, that have been more educational for me than LessWrong, but I can count these on the fingers of one hand.
Some of my friends have claimed that reading LessWrong systematically (and perhaps participating in the comments and attempting to write posts) would generate more value for an undergraduate than a typical core college class (with the possible exception of technical classes specific to the person's major or area of specialization). I'm curious about whether readers agree with this assessment. Do you feel, for instance, that LessWrong provided you with more valuable human capital than your introductory general chemistry sequence? What about comparing LessWrong with an undergraduate "intro to philosophy" class? Or an undergraduate intro class on the history of economic thought? At what percentile would you rank LessWrong relative to your college classes?
A second related question is whether there's a possibility of building a college course -- or college-like course, perhaps a MOOC -- specifically revolving around mastery of the content in LessWrong (perhaps starting with the Sequences). Would such a college course be possible to design in principle? How would such a college course compare with core requirements for undergraduates today?