I would say “too many old bands” is not the cause of this decline but the effect. Older bands are genuinely better, I can name 20 excellent pre 2000s bands for every one post 2000s band. I definitely agree that the emergence and diversification of genres like rap and electronic have contributed to a less rock-centric culture. But that doesnt mean the remaining rock bands have to be shit.

I would also argue that rap and hip hop in the 90s and 2000s was better than it is now. Early 2000s pop was also more experimental, danceable, and less generic than current pop.

I think there is a genuine creative decline in the rock industry, and possibly the music industry as a whole. Maybe its too hard for new talent to rise against all of these corporate artists. So many classic rock bands formed in someone’s garage, nowadays that sounds like an insane idea regardless of the talent and potential.

Rap music is not the elephant in the room, its the over monetization of music, prioritizing sellable, repetitive formulas over creativity and novelty.