Actually, it was an accidental success: a low-budget movie from a record producer who had just the right artists already under contract. It had only one star with any name recognition and he (John Travolta) was largely known for a foolish adolescent role.
1. Travolta's career might not take off as well.
2. Disco does not go through a 1978 revival and gradually fades away, making room for earlier punk/new wave.
I did a thread about this a year ago. Someone said that the New Romantic movement of the early-80's was influenced somewhat by Disco. Maybe we don't see groups like that if there is no SNF.
Without SNF, here's an alternate scenario that could happen:
1. Obviously, without SNF, Disco isn't over the top big by the late-70's, even though it is still popular to some degree.
2. With disco decently popular, but not annoying the crap out of everyone, the creators who made the movie Rock N' Roll High School(which came out in August 1979) make it a disco film instead(After reading the trivia section on IMDB, Disco High was one of their original ideas before settling on Rock N' Roll High School).
3. A few months later, you had the roller disco movies released(Skatetown, U.S.A. and Roller Boogie). With those three movies, I wonder if you see a later popularizing of disco that carries into the early-80's, and I wonder if we see Travolta in any of those movies(I don't see him being the male lead in Roller Boogie, because Jim Bray was perfect since he was a champion roller skater, but maybe he plays a big role in Disco High or something).
.
