The number of writers who can sustain themselves solely by the income they earn from freelance or fiction writing is diminishing rapidly. There are many other ways a writer can earn a living writing, but those are mostly in professional environments (e.g. marketing, corporate communications, technical writing) where a B.A. is generally a required credential to even get a resume looked at. To open those doors, what major the degree is in doesn't matter nearly as much as simply having a completed degree.