It was a pseudo-revival of mid-century folk music. It didn’t last because much of it didn’t have genuine proletarian roots like real folk music. It mimicked the aesthetic and sounds of folk music but none of the content. It never will when it’s just wealthy urbanites cosplaying as poor country bumpkins.
Folk music and related genres (like soul and country and blues) have all suffered for the same reason. Their class character is fake and purely aesthetic today. At least, for the super mainstream bands that make it on the Starbucks Spotify playlist.
There was a megathread a while back about Woody Guthrie. His music lasted because it captured a genuine aspect of working class America in a way that stomp clap hey never can. This Land Is Your Land was a political song. We don’t do that enough anymore, in the name of mass appeal and profit and merchandising. Even Bill Withers, who was merely center-left as far as I know, made music that mattered with lyrics opposing racism and war.