Have you heard Those Poor Bastards? You have some dark, psychedelic, death-themed lyrics there, and it's country music.
Have you heard RATM? Hard to find anything more angsty and rebellious, and yeah, it's classic rapcore. (or maybe you have in mind "rap" as hip-hop music. There would be something there too)
And really, rock'n'roll today is music for a glass of wine. Compare it to noizecore, screamo, black metal, grindcore.
Rock in general is too wide to have any specific discussion about it. On one hand, during the 70s we had a wave of progrock, then new wave in the 80s. On the other hand, there was drugged glam and rebellious punk, then some poor attempts to go back to the rebellion via grunge.
I, personally, don't see rock as a genre, it's a huge cluster of genres. "Rock" means nothing, like "electronic music". You could as well say just "music".