I think there's something to be said for knowing the craft. But you can learn any craft without formal training, and sometimes formal training can actually get in the way. Likewise, the more trained you are, the more likely you are to take that training to heart, and particularly since genre writing is always considered "beneath" literary writers, if that's what you want to do, you're unlikely to get a lot of help from an English department.

College doesn't exist to somehow magically let you learn things you can't learn elsewhere - it exists to provide what is necessary to teach what you can't seem to grasp on your own, and to give you a piece of paper that says you're competent at what you know. That piece of paper doesn't matter when you're shopping manuscripts around, only the knowledge does.

Then again, you're talking to a guy who cut a straight month of math classes at JC, so grain of salt. I still got an A when I came back for test days, though, so make it a small grain.