Anything you hear on the radio nowdays basically is for people who don't want to learn, or have insight. That includes all genres (rock, rap, punk, r&b). Stop listening to the radio, and start investigating music, and seeing what YOU like. The radio is for people who want to be popular in high school, and people who like to dance. Good Rap exists mostly outside of mainstream rap. If you want to hear good rap, check out these guys:

Atmosphere, Jedi Mind Tricks, KRS-One, Rakim, Afrika Bambataa, Run DMC, Biz Markie, Chubb Rock, Haiku d'etat, Wu-Tang, The Roots, Digable Planets, MF Doom, De La Soul, A Tribe Called Quest, (2pac, Biggie, Big L, Big Pun, &; the ODB RIP), Nas, The Artifacts, Outkast, Pharoahe Monch &; Prince Po, Common, Jeru the Damaja, Afu-Ra, Gangstarr, J-Live, Busta Rhymes, The Fugees, Redman, Madlib, Xecutioners, Peanut Butter Wolf, Beastie Boys, and Jay-Z, Erykah Badu, Lauryn Hill, Bahamadia, Matisyahu, Yellow Man, and, that's about it for good rap now-days, forgive me if i forgot some importnat people, but I'm just pulling this out of my head real fast.