Well let's see... it's not a show about:

1) Doctors having sex
2) Cops having sex
3) Lawyers having sex

or

4) A "reality" show loosely based on some contrived situation but really about sex

So that makes it really difficult for executives and focus groups to give it a green light.

@3,

Firefighters... cops... in TeeVee they're mostly interchangeable.

@1 MTM was about a TV station, WJM. There have been plenty of shows about TV shows, because Hollywood loves nothing more than to talk about itself and hack writers only write what they live.
Lou Grant, however, was a fabulous TV show about a newspaper. It only won a ton of awards and was one of the most critically acclaimed shows of its day, so I can see why it was unknown to someone who watches BBC shows and thinks they're original.

This discussion about contrasting British newspapers reminds me of a scene from Yes, Prime Minister -------

Hacker: Don't tell me about the press. I know exactly who reads the papers: The Daily Mirror is read by people who think they run the country; The Guardian is read by people who think they ought to run the country; The Times is read by the people who actually do run the country; The Daily Mail is read by the wives of the people who run the country; The Financial Times is read by people who own the country; The Morning Star is read by people who think the country ought to be run by another country; and The Daily Telegraph is read by people who think it is.

Sir Humphrey: Oh and Prime Minister, what about the people who read The Sun?

Bernard: Sun readers don't care who runs the country as long as she's got big tits.

https://www.youtube.com/watch?v=VUVix0STUqo