Because there was. When was the last time you heard something afrocentric, positive, or uplifting on the radio? When was the last time you heard straight lyricism on some "Battle the unknown MC" shits? Maybe some silly shit like Redman, Biz, or Sir Mix A Lot made? How about some dance shit? Shit, niggas had a whole era of that in the mid 00's, where did that go?
Naw, it's murder death kill spin the block on the opps pussy eat ass suck dick scam he ain't got money shit on the radio now and aside from the odd Drake or Kendriock joint, that's really about it.
Think about this: The remix to BDP's "You Must Learn" hit #15 on the Hot Rap Singles chart. De La Soul's "Me Myself and I" was #1 on the Hot Rap Singles chart and peaked at #34 on the Hot 100 while Biz Markie's "Just A Friend" cracked the top 10 at #9 on the Hot 100 and #1 on the Hot Rap Singles chart. Hammer was #1 across the board with some of his shit, and that's with niggas clownin' him for being too commercial. PE had the #4 album in the country with Apocalypse 91...Enemy Strikes Black. Das EFX hit #1 on the Hot Rap Singles chart and #36 on the Hot 100 with "The Want EFX".
I could go on... But the real question is: When was the last time we had any sort of diversity in hip hop like that on the radio?