I first read this observation in an article now lost to me, but it reflects my own memories at the time is this:
At bars & clubs that were playing alternative rock at the time, people who went up to dance usually danced by themselves or in groups of friends, but the idea of asking a stranger to dance with you as a couple had fallen to the wayside.
The rise of swing music in that scene allowed people to once again approach someone they found attractive and invite them on the dance floor, and back then, everybody was having a good drunken laugh dancing silly to the music and being able to proceed from there to maybe asking for a phone number after.
However, as Swing Revival got popular, Swing Music Nights were gradually taken over by University Swing Dance Clubs and the like, and the original kids who'd dance to Zoot Suit Riot found themselves displaced on the dance floor by people showing off how hard they practiced The Lindy Hop, and those Dance Clubs generally only drank water while they were there, and if bars learn the crowd they're attracting on those nights are not drinking alcohol, then what's the point of holding those nights?
So it obviously didn't kill the Swing Revival by itself, but once the Revival lost the people who were having fun with it in the first place, that definitely accelerated the end of it.