It's been over 15 years since Seinfeld finished up its nine year run in 1998, and, since that time, there's been no other show, or, at least, certainly no other sit-com, that has captured the public's attention in the same way. Why is that? And, in this modern day and age, is such a thing even possible anymore?
While there are many reasons for Seinfeld's success, there are two main ones. First, it had one of the strongest casts in television history, which each of the four actors being talented enough to carry their own show (even if their post-Seinfeld vehicles didn't necessarily bear this out). But, with the show's multiple plot line structure, each week, we did watch, in addition to the main Jerry story, what was essentially a second show about George, Elaine, or Kramer. In addition, in Larry David, the show possessed a creator at the top of his abilities, given the freedom, as ratings climbed, to do exactly the show that he wanted.
The second reason for the show's success, was that it was given time to develop. When it first premiered, The Seinfeld Chronicles, as it was initially titled, was a decent show that had some promise, but was watched by almost no one. Despite the terrible ratings, NBC gave the show time to grow, and as the show matured into the well-oiled comedy machine it became, audiences found it, making it one of the top sit-coms of all-time.
And this is why it's hard to imagine another show having the same impact today. Seinfeld premiered in a different television landscape, and it's hard to imagine a major network having the same patience today. There are still talented casts and creators, but these days they're bringing their best work to cable, presenting their work to an audience that's loyal, but that can never match the size of 1990's broadcast television.