Just as many "experts" proclaim that early-Elvis and early-Beatles were the best work that they ever produced, I think we're going to have to accept that new episodes of "Seinfeld" will never match up to its predecessors. We can individually enjoy these new shows for whatever humor strikes a chord within each of us, but Seinfeld-fans as a whole can no longer agree and say, "Yeah, that was funny!" I try to keep the belief that becoming popular to the mass audience has no bearing in keeping the "edge" of one's act, but now I realize that being a #1 hit for your network carries a burden that somewhat curtails the creativity and biting wit that produced got you attention in the first place. So if we were to put past Seinfeld episodes into historical classification, I'd go along these lines:
1989 - 1990 Dawn of a new era: fresh concept for a sitcom, with a lot of experimenting, hits and misses of course.
1991 - 1993 The Golden Age: the peak of the "Seinfeld", breaking barriers and setting standards.
1994 - 1995 Complacency: after finally achieving mass recognition, storylines begin to stagnate, memorable shows get far and few between.
1996 - ? Fall of Rome: drunken with success, the original premise and spirit of the show is completely forgotten.