It's a phrase I've heard way too many times, and one that doesn't really have much to do with Jerry Seinfeld.
Jerry Seinfeld started a revolution. But many times, revolutions just result in chaos, death, and war. In the case of Seinfeld it resulted a lot of shitty comedians in suits and the death of the comedy boom in the early 90's. Don't mistake that as an insult to Seinfeld, in fact, it's a compliment. Jerry Seinfeld is a comedy textbook. Every sentence, word, and syllable he utters has a specific purpose. His jokes are laser guided missiles. But those shitty comedians in the 80's boiled down his act to: "What's the deal with airline food?"
Seinfeld is to stand up comedy what Les Paul is to guitar players. Sure, Les Paul doesn't penetrate your soul the way Eric Clapton or Jimi Hendrix did. But he is a technical master that can wail on the guitar in a way that made even Clapton and Hendrix jealous. Seinfeld doesn't have the raw, pent-up emotion that Bill Burr has. Or the calming, guiding pragmatism that Louis C.K. has. But ask Burr or C.K. what they think of Seinfeld, and you'll think he's some kind of god. He writes jokes with deadly accuracy that 10,000 comics in the 80's tried - and failed - to replicate, and paved the way for some legendary comics.