Very few shows can be pinpointed to the very DAY they jumped the shark. In my opinion, Saturday Night Live is one of those few.
On October 3, 1992, the now infamous Sinead O'Connor episode,in which she ripped up a picture of the pope, aired. The once cutting edge comedy now had the same "cutting edge" as a pair of kindergarten safety scissors, as SNL caved to the outcry of the critics and the exclamations of "blasphemy". NBC, incidentally, has never allowed that clip to be shown again in reruns of the show.
Because SNL at that moment declared that popular consensus, rather than creative imagination, would run the show, they effectively gave complete and utter control to the network censors. This left a number of "taboo" subjects, and stifled the creative potential of the "not quite ready for prime time players".
While I will readily admit my skit suggestions would be slightly over the top for most network TV shows, the fact remains that many subjects HAVE become beyond reproach, and SNL can never again have the punch it once had, no matter HOW brilliant the cast.