Why did first-run syndication comedies not continue to be produced after about 1993

[TMC]

Mama's Family and maybe to a lesser extent, Charles in Charge, are probably the most successful examples of sitcoms to be aired in first-run syndication at least from roughly, 1986-95. Was it simply the emergence of UPN and The WB come early 1995, as well as Fox finally expanding to seven nights a week? This meant that producers had more options at their disposal (unlike when it was still just "The Big Three" of ABC, CBS, and NBC) instead of taking their chances with a decidedly less stable syndication market?

Is it also because it's more of a challenge for stations to sell half hour shows like sitcoms because unlike with an hour long drama, they naturally need another 30 minute show to serve as a companion piece of sorts. This is from what I've gathered, why The CW abandoned sitcoms shortly after the UPN/WB merger.