Napster exploited an already exploitative and dying industry. Napster hurt the labels and the biggest artists, but didn’t make much of a dent outside of the mainstream. The rise of indie rock (and labels) and genres like hip-hop, country, and punk supporters that claim. Or, at least, that’s what my friends who are currently touring musicians say.
If anything besides greedy executives and the consolidation of radio stations and record labels (eg, boomer causes) killed the music industry then it’s probably streaming. Spotify, for instance, affects almost all tiers and genres of music, rather than arena rock and top-40 stuff. That’s a far less ridiculous claim than claiming that the likes of Napster, Limewire, etc. though industry insiders love to blame these companies for their own incompetence.