If you want to write literature, as with The New Yorker, or work in publishing or journalism, then yeah, college is a great advantage.
But if you just want to write well, and read great works that resonate with you, then find where your passion is, what books you enjoy the most, and go to those author's websites and find where they learned and how they do their research.
All the information is there. I did it all before the internet, and you can, too. There's a great lineage there that you can discover on your own, such as how James Herriot learned from reading Conan Doyle and Conan Doyle learned from reading Bret Harte.
Louis L'Amour also learned from Conan Doyle, and he dropped out of high school because "School was interfering with my education." As he worked in the merchant marine and rode railroad cars, he read everything he could put his hands on. Same with Jack London, self-taught all the way.
The best thing about college is the camaraderie and being exposed to books, music, and cultures that you wouldn't ordinarily know. But you can save yourself so much money and time by getting an apartment in a college city or travelling and so on. Then you'd actually have something to write about than your experience in slogging through term papers on “Industrialism in 19th Century Novels.”
So yeah, many writers have gone to college, of course. But many of those, like John Grisham, Conan Doyle, Keats, and recent Nebula winner Elizabeth Moon, studied law or medicine or science. There's also many writers who went to college and then dropped out, including Anne Lamott, August Wilson, Cormac McCarthy, Gordon Parks, John Muir, Mark Twain, Richard Bach, Sam Shepard, Tom Stoppard, Walt Whitman, and Woody Allen.
To sum up, it all comes down to applying yourself. Focus and discipline. You can do that in college or on your own, but in the end that's the major determining factor of whether you'll succeed in what you start.
The ultimate goal of the educational system is to shift the individual the burden of pursuing his own education.
- John Gardner
No university exists that can provide an education. What a university can provide is an outline, to give direction and guidance. The rest one has to do for oneself.
- Louis L'Amour
I don’t think a college degree is necessary to become a good writer. I’m not even certain it’s an advantage. College probably won’t hurt you – if you don’t take it too seriously. But far more important, I believe, is broad general experience: living as active a life as possible, meeting all ranks of people, plenty of travel, trying your hand at various kinds of work, keeping your eyes, ears, and mind open, remembering what you observe, reading plenty of good books, and writing every day – simply writing.
- Edward Abbey