To throw in my own experience: I have a BS in Physics, and I'm currently finishing an MS in Materials Science. I have friends who are working on startups while they do their CS PhDs. I hang out with electrical engineers, drink every Friday with a group of chemists and biologists, and play games with a selection of librarians, psychologists and English majors. And in a couple of months I'm starting an awesome HPC job which I found because of the people I met in school.

The advantage of a university is a high concentration of diverse, smart, and interesting people. You get to spend several years in an environment with a lot of people who know things you don't, a lot who don't know the things you do, and you are there specifically to talk to each other. Sometime's they're the same people, because humans don't overlap perfectly. Not everyone you'll encounter is worth it, but it's easy enough to find the ones who are. And you'll all have the time to hang out, which can be hard when you're dedicating yourself full-time to something else.

If you're really an excellent developer, and you're absolutely sure that this is the work you want to do for the foreseeable future? You can probably make it work without college. But that doesn't mean you should.