Although I don't think anyone is going to argue that the show has definitely gone way downhill in the past decade or so, there was a time when this variety show was the top dog in comedy. With a constantly changing cast and no permanent theme, the show was able to easily adapt with the times - something I think they actually did quite well until recently.
The Year was 1975
I think that most people probably recognize Dan Aykroyd, John Belushi, and Chevy Chase in that above picture (the others are Jane Curtin, Garrett Morris, Gilda Radner, and Laraine Newman) and they were the "freshman class" of SNL. They were jokingly referred to as The Not Ready for Prime Time Players and none of them were famous at the time. That would all change dramatically as SNL ended up being a sensation.
It was determined that this show would not have a recurring host, but instead a different host each week which was a pretty novel and unusual approach to television. A "lotta hair on his head still" George Carlin was the very first ever host of SNL. Other sketches included Belushi playing a foreigner learning English and Andy Kaufman appeared to do his famous (and I'm not sure why it is famous) lip syncing of the Mighty Mouse song.
There was also a rather tame but still adult-oriented "Muppets" segment called The Land of Gorch which failed to really fit in with the rest of the show and was cut after the first season.
One of the main reasons that The Land of Gorgh was so unpopular is that Henson's staff were not allowed to write the dialogue due to rules created by something called "The Writers Guild." Henson and the SNL writers themselves did not like the arrangement, and it became evident very early on that neither side was putting much effort into the sketches and it was agreed after one year that they would part ways. One wonderful thing did come of all this though: English illustrator Brian Froud was impressed with the puppets on Gorgh and he and Henson would later create The Dark Crystal.
first ever monologue from the official SNL channel
Not many people are aware of this but Saturday Night Live actually accidentally came into being because of none other than Johnny Carson. He wasn't at all involved in planning or design of this show but as the overworked "King of Late-Night Television" Mr. Carson demanded that he receive 2 days off a week as his show was a 7-night-a-week affair at the time. Fearing that denying this change would result in Carson leaving the network, NBC complied and ended up filling one of the weekend time slots with Saturday Night Live.
SNL pretty much sucks now and I don't think very many people even pay much attention to the fact that it is still on every weekend in the same time slot. For those of us that were alive in the early years it was EVERYTHING. Virtually everyone that was on the show in those days went on to accomplish great things in comedy and being cast on SNL was pretty much the best thing that could happen to a comedian's career.
It wouldn't surprise me a great deal if they make it say 50 years and then hang it up. Their most recent season premiere's viewership was down 30% from last year, and last year's numbers were already disappointing.
All good things have to come to an end eventually... and at least in my opinion it might be SNL's time.