This isn't worth a whole post, but have you ever noticed that sitcoms, more than other types of TV shows, tend to start out being described as cutting-edge and innovative, and, after they become successful, begin to be described as bland and conventional?
The ultimate example of this is still The Cosby Show. In 1984 critics called attention to its innovations: no plot, stories based on small realistic details, parents who were smarter than the kids. Within two or three years, it was routinely described as the apotheosis of bland, conformist sitcommery, so much so that the producers of iconoclastic Married With Children wanted to call it "Not the Cosbys." The Cosby Show hadn't really changed its style, though it wasn't as good as it had been in its first season; it's just that once a sitcom becomes successful and imitated, critics have a tendency to turn on it. I think this is because many TV critics don't particularly like sitcoms and aren't very good at evaluating them, so they tend to judge a sitcom by how different it is from other sitcoms. Once the rest of the TV industry catches up with a sitcom, it's no longer "different" and can be slammed accordingly.
Other examples of sitcoms that lost some of their cachet after they became too popular: Everybody Loves Raymond, Family Ties, Leave it to Beaver, All in the Family.
All in the Family, you'll recall, was slammed in the 1976 movie Network as an example of the blandness of television: "Nobody gets cancer at Archie Bunker's house," Howard Beale points out. I've always thought it was in reaction to this line that the writers of AITF gave Edith breast cancer in a later episode. Of course, citing AITF as an example of TV's unwillingness to deal with real-life problems is incredibly stupid, yet another example of what's wrong with Network, namely that that reactionary old sourpuss Paddy Chayefsky had no idea of what was actually on television at the time. But it also indicates how even the most cutting-edge sitcom will get accused of blandness as soon as it gets successful.