There's a difference between what has critical acclaim and artistic merit and what is popular. That's why Studio 60 was cancelled, while the Simpsons has been on far too long, it's why we've got American Pie 9 or whatever the hell it's on now, it's why in America shows get ploughed into the ground until you just can't stand to watch them anymore and in the UK shows have maybe a two or three series shelf life.
I'd much rather have lots of good shows than thousands of hours of the same show because it gets ratings.
Ratings != Quality.
Quantity < Quality
It's the reason the X-Factor is an ITV show.