Depends ...

... The self-epublishing bubble | Ewan Morrison | Books | guardian.co.uk. (Hat tip, Dave Lull.)

This may be so for those who take up writing in order to get rich. John Jakes once told me that the thing that was most surprising when he had his first best-seller is how many people he met who thought it was his first book. It was, in fact, his 26th. I think most people who write  do it for reasons other than becoming rich quick.