I'm pretty sure most/all the people who think that college gives you a unique social experience that you can't get elsewhere are just suffering from confirmation bias, and also perhaps want to justify why they spent so much money.

I went to a top-tier 4-year university, and did develop several life-long friendships, many of which have led to introductions to other people, which have further increased my social and professional circles. It'd be easy to say if I hadn't gone to college, I wouldn't have that now, and, well, that's actually true... but it's missing the point. I'd still be me, and I'd still have the same drive to meet people and take advantage of opportunities. My life would be different, certainly, but I doubt it'd be less socially fulfilling.