It's not just about the lack of literary skills. The problem is deeper, says Martha Southgate who investigates this question in her beautiful piece in the NYT:
Consider the case of Edward P. Jones. He published his first book, “Lost in the City,” in 1992 (he was 41 at the time) to much critical acclaim and a number of significant honors, if not huge sales. He returned to his day job at Tax Notes magazine, where he remained until he was laid off 10 years later. He then wrote “The Known World” in about six months — though he told me he’d been thinking about it nearly those whole 10 years. The novel won the Pulitzer Prize.
When asked why he didn’t make the leap to full-time writing sooner, Jones spoke firmly: “If you’re born poor or you’re born working-class, a job is important. People who are born with silver spoons in their mouths never have to worry. They know someone will take care of them. Worrying about not having a job would have put a damper on any creativity that I would have had. So I’m glad I had that job.”
I know what Jones is talking about.
It is a good piece. Go read it here.