I think for this argument to be sound we have to define what artists would be included. Is it a survey of popular music? All music? There is a lot of intelligent hip hop out there. There is a lot of shallow rock out there.
Generalizing about any genre is pointless.
Edit: And I put intelligent in quotes because who is to say that using the word money or (less so) bitch even means there is not an intelligent point being made.
I admit I was trolling, but the amount of rap out there that plays into the macho-gangster-materialist-misogynist stereotype is obscene. Decent rap does exist, but gangstacrap still dominates the genre. Other genres of music have their own dominant stereotypes that are equally vapid, but seldom as scummy.
You're conflating stupidity with poor taste, but they're clearly independent. Consider the Wu-Tang Clan's lyrics which are more intelligent and have a level of wordplay that is non-existent in rock music, but at the same time can be the most offensive thing you've ever heard.
I'd agree but there are shades of grey where gangsta rap can actually be quite enlightening to listen to. Big L was very very _hard_ yet still had a real story to tell, and real perspective.
Generalizing about any genre is pointless.
Edit: And I put intelligent in quotes because who is to say that using the word money or (less so) bitch even means there is not an intelligent point being made.