This doesn't answer the question directly, but I think it plays a part. Hip hop is not sufficiently recognized as an art form, the way many other genres of music or creative endeavors are. And, that impacts the music and culture in a lot of ways.
1. Without sufficient understanding that the music is artful and creative, there's a greater demand for it to be literal, which leads to the you have to live what you rap about trap.
2. For the same reason, the topics about which it is "acceptable" to rap become narrowed....Hip hop wasn't always this way - I'm an older guy (compared to most on NT) and an East Coast, boom bap, elitist, but will say this about my very kind. If most of the Native Tongues crew came about today, MY OWN PEERS - people who are among the biggest ATCQ and De La fans would likely be calling them out for being Emo-rap, or tight-jean rap, or something. So, we're all guilty of it.
3. The discourse around the music rarely elevates beyond "that's fire," or, "he's wack." And, I'm not talking about snide remarks on a message board. People can always be sarcastic, trade jabs, and clown on acts they don't like, that's fine. But it also takes people to go out, become educated, successful, have some kind of voice or megaphone, and then speak about the culture that formed them with reverence, eloquence, and depth to build a social understanding of that art as meaningful. I know the odds are stacked against many of the consumers of hip hop to achieve that sort of influence, but nonetheless, the absence of this hinders the ability of the music to evolve overall.
Finally, I'll say this - artists who do a very good job at just being themselves from the very beginning suffer less from the struggle to evolve and maintain their "street cred." And, frankly, rappers who understand political and social issues and integrate that into their rhymes fare extra well in this regard because being successful professionally doesn't eliminate widespread social injustice, so success doesn't bring forth the same dilemmas when your "cred" is tied to fighting for what's right as opposed to selling crack.
