Yes, but Seinfeld was a hugely popular sitcom and for some reason it's regarded as one of the greatest of all time. Though, if you watch the first episodes, it's a wonder they took that chance with it. I also understand the popularity of Friends, but I never got it at all. it spoke for a generation, sure...
The REAL stinker sitcoms were in that post Seinfeld era... ABC's terrible family sitcoms (though I shamefully admit to digging George Lopez's one) that tried a little too hard to be the 1980's TGIF style family sitcoms... the myriad of Friends/Seinfeld/Will and Grace wanna bes that lasted a season or less and quietly disappeared. They even tried a BAD US remake of Coupling. The sitcom was all but dead... and all the sudden, The Office, Two and A Half Men (I know your feelings about the show, but I'm mentioning it for the sake of an example), and HIMYM popped up... thus saving the sitcom, albeit not quite as we know it. Things go in cycles... you get a bunch of really good movies, TV shows or something, then a bunch of meh ones... then bad ones, then terrible ones, then you get great ones again. Like how I feel about 1970's cartoons... the 60's brought a bunch of great ones, then one because so popular everyone copied it for a decade. Then someone did something else, and things changed. That's the nature of entertainment.