"Over 26 years, the hitrate is not high enough."

TV New showrunner Steven Moffat on the writers of Doctor Who:

"Mostly they were middle of the range hacks who were not going to go on to do much else. Over 26 years, the hitrate is not high enough. There are people who have worked on Doctor Who and gone on to great things, like Douglas Adams. I just think most people thought this was going to be the big moment of their lives, which is a shame. As a television format, Doctor Who equals anything. Unless I chose my episodes very carefully, I couldn’t sit anyone I work with in television down in front of Doctor Who and say ‘Watch this’."

... in 1995. He's since become slightly embarrassed about this.