Yes, you could stay home, or move elsewhere, and be one of a handful of people like yourself. Or you could go and be surrounded by thousands of brilliant, amazing people for years of the most formative years of your life.
The benefit of going to a good school isn't the classes, it's the people.
As you move down the scale that becomes less and less true. People go, learn whatever they learn, get few if any connections, and wind up with a pile of debt.
So, we've created an incredibly regressive system.
One other thing to note. When people form those friend groups it's not just about who's their intellectual peer, it's also about who came from similar backgrounds etc. It's an engine of division as much as anything else.
I agree that the value is there for some individuals, but I disagree that this is a good thing for society as a whole. If you get accepted to Harvard, it's almost certainly worth your while to go. College still remains a finishing school for the elites in our society. Some people bubble up from the underrepresented portions of our society, but they remain the exception, and will continue to be so until something changes.
I've included a couple links below that explain the disadvantages some groups face when attending college.
http://www.pewresearch.org/fact-tank/2016/07/27/blacks-with-... https://www.vox.com/2017/9/11/16270316/college-mobility-cult...
By bucketing all these experience together as if they're the same experience does a tremendous disservice to those who can least afford to make a six-figure mistake.
Sometimes when coworkers find out there is a remark like "Oh wow, I never realized that." Imagine after somebody had brought up their alma mater and I remarked "Oh wow, I never would have realized you went to college.."
Recently, a friend suggested that I avoid mentioning this to prevent stigmatization. I realize now there are probably a bunch of people who think badly of me for it, much to my bemusement. Until my friend mentioned it, it hadn't crossed my mind that anyone would interpret that as "this slob couldn't even finish high school".
So this whole "Is college useful thing" is basically only relevant if you never want to live anywhere else. Immigration is far harder if you do not have a degree.
One reason why it's so easy to sell, is that college is a near universal experience for the middle and upper classes, and being an expensive experience, people credit it with much of the personal growth that happens in one's early 20s. They also credit it with making them good at their field.
"I really learned how to think in college"
"I really learned how to be apply myself in college"
"I really learned computer science in college, which wouldn't have happened if I went via some other path.
etc.
It's far too painful for most people to think "I could have been an equally skilled person if I'd spent that time doing something else".
I come from a long line of people who've succeeded without going to college. When I tell people I've known for a while that I dropped out of a community college they usually seem stunned and surprised that someone could actually have a reasonably intelligent conversation with them (and be a decent engineer) without that history.
My experience is that you can read books on the humanities, and CS, and get work done AND not kill yourself in the process. Maybe the road is a little longer in some ways, but you also come out of it without debt, and you get the benefit of having a very different set of formative experiences than your peers.