An alternative view is: "If you're already successful, everything you could learn at a college you can also learn out of college (see: the internet)".
First, few are so motivated that they'd devote years to self-learning at the same scale as university provide. Next, it would be difficult to put together a cohesive curriculum for yourself because you don't know what you don't know. Relatedly, understanding the arc/trajectory to pick it difficult, and to do it all alone with no guidance means there's no one qualified that you can ask questions from on the daily. It also ignores the value of mentorship, learning from your peers, and being inspired and pushed by your environment. It also is isolating and does not give you any social benefits, business or personal networks.
Career-wise this has been a terrible life choice for me and I advise people to go to college for precisely the same reason you do. On the other hand career and material gain are only one aspect of life, I can't say with conviction that I really wish I'd done anything differently.
So, yeah. It seems like a completely correct view. My guess is that it will only become more and more correct with time, as the internet provides all the building blocks that colleges provide currently. The knowledge is already there. Credentials are there for some professions (Github > sheepskin). Networking is probably the hardest part, but hardly sounds undoable.
It is difficult for most to self-motivate 4+ years worth of self-study in isolation. Few would do that on their own. Further, getting a random stranger to mentor you for any real period of time is a difficult proposition without anything in return. Typically this only happens in extreme cases such as if you are a superstar and "worth their time."
If all you do is stay in your dorm and never venture out, then you're not getting much out of what the university offers, so that's not particularly relevant. You can also just not attend any classes either but that's not much of a comparison.
You're also ignoring majorly important components such as opportunistic learning from peers, being motivated by your environment, and having others guide you through subject matter when you don't know what you don't know. The internet cannot replace any of that as effectively.
Regardless, as mentioned before, if you think colleges do choose the best textbooks, you can find what textbooks they're using very easily.
My experience is that the best thing you can do is sample many textbooks and keep the ones you like best and are most likely to learn from.
That few people are willing to self-motivate for 4 years doesn't invalidate the possibility of doing it. I would also question the necessity to study for 4 years to learn most subjects.
The point about staying in your dorm is that if you're studying (i.e. not going out with your friends), it doesn't matter whether you're doing it at home or in a college dorm. You can socialize in other ways.
Serendipitous learning happens outside of colleges too. Etc. Etc.
Having been through college, and having learned a lot of things on my own, the only thing I think (some) colleges provide is just sheepskin prestige. If you want to work for a company that screens based on what university you went to, don't make the mistake of skipping that part. Learning-wise? I don't think it makes much of a difference.
http://www.bloomberg.com/news/videos/2016-10-17/the-david-ru...
One enters college to better themselves and for the purpose of a collaborative education.
One enters college to improve their ability to interact with the world in a meaningful fashion.
For those in the former camp, college is a means to an end. Those in the latter value the aspects of a collegial environment that you can't get elsewhere when learning. I find myself in both camps, I'd love to return for a PhD but it's such an economically poor decision that I don't.