When it comes to any form of music, most people will always argue that the "good old days" are better than what's currently happen. However, rap is continuing to evolve just like every other genre is growing. Most people blame to current style on Lil Wayne. Truth be told, his time will come and go just like everybody else came and went.
If we look at the music itself. Primitive music, had no structure, no melody, no harmony, just sound. Then you had music evolve into wonderous things lime symphonies and overtures, these had structure, and melody and harmonies. Then Jazz came along, which through out the "classical" style of strict structure. Jazz then devolved even further into rock. Which rock is the same 4 chords played over and over again. Then rock devolved into hip hop/Pop, whoch eventually devolved all the way down to rap. Rap has no structure, rap has no melody, rap has very little musical quality to it. Misic reached its pinnacle in the romantic period. Rap is primitive form of music. Rap is simply the combination of a repetitive beat, accompanied by words, most of which you can not understand. So essentially since you can't understand the words, rap is nothing more than a repetitive beat playing over and over. So yes Rap is a severly devolved form of music.
Rap and hip hop is devolving along with the rest of society. The people who produce the music and the videos know what will sell to the mass majority of people and the mass majority of people are shallow, stupid creatures. Therefore you get shallow, stupid music. Three more words
Rap is supposed to mean rythme and poetry and never, never in my life time have I seen a rap song with poetry in it. Maybe I'm blind or close minded, but I've listened to the allegedly "greatest" rappers like tupac, Notorious Big, snoop dog, etc and, to me, the lyrics look pretty much the same. The lyrics are lame and dull. Of course there is some exceptions, but for the most part it's foolishness. This is why I think that rap has never evolved and it will remained the same which is monotonous.
Rap music for the majority part that we listen to on the radio is devolving hugely. Not only has it gone down and degraded for the past 10 years, it is less creative and takes no effort for the most part. Rap that we often hear today is full of vulgar, cursing, violence and other offensive topics that are detrimental to a human being.