Eh, what genre are we talking about? And how far back do you want to go? Because Kendrick absolutely blew the doors off of a dying rap/hip-hop scene when he released good kid, m.A.A.d city. Granted, that was 2012, but Dre had turned into more of a mogul/producer, Snoop was hanging with Willy Nelson and Martha Stewart, and Ice Cube was doing "family man" movies. The genre was in rough shape for around a good decade or so. The reason you're seeing so much of that "thug shit" now is because he massively helped revive the genre. So, of course you're going to see a bunch of shitty rappers trying to get in on the "gold rush".
Like I said, country and rock are about the only genres still mostly dominated by "old-school" bands/artists. And while there have been a few breakouts like Greta Van Fleet, they mostly broke through on "old" sound. But, rock went through a similar decade in the 80s where the sound wasn't really changing and it was mostly dominated by bands that had already "made it".
@Amod Can we break this discussion off into another thread? I'd like to continue it, but this derail has gone on long enough.
