The average person in their 40s isn't going to be the audience for Rap, the only reason you remember the likes of P Diddy and Kanye, etc, is because they were huge hitters in the early 2000s so naturally you'll still associate the genre with them, where as those who do keep a finger on the pulse know there's bigger artists now in terms of appeal, no one is waiting for the next P Diddy or Kanye song (outside of the memes from it) but people do look forward to new music from the likes of Doechii, Kendrick Lamarr, etc.
Even the lesser known up and comers are doing some good shit
And even go back a couple of years, DJ Premier did some beats for artists like Ab-Soul which went fucking hard
And yeah there's still trash out there, this shit was popular on TikTok for a bit a few months back
Sorry this post went on a bit, to sum it up, yeah the like of Diddy and Kanye are huge names but them going through shit now for what they've done isn't going to crumble or destroy the rap scene.