First off, I want to say that I enjoy Rap. I think that Tupac was a musical genious, and Public Enemy was a great innovator.
Second, I think that Rap is slowly degrading, and will be gone or heavily changed by year 2020.
Why? Here are my reasons.
#1: What is most desired in Rap culture? Quite simply, it is power. Rap music is loaded with lyrics concerning ammassing large amounts of money, the acquisition of "hoes", a presumed sense of superiority, and other symbols of power. Rap music is also one of the only genres (with the exception of shred metal) that demonstrates power through competition. Clubs are often filled with rappers performing "rap-offs"" in which the musician tries to deface his opponent with his "rhymes".
#2: How does one gain power in the Rap industry? The easiest way for a rapper to do this is to create a Rap song with widespread public appeal. To do this, all rappers need is a catchy backing beat with lyrics concerning symbols of power.
#3: What does this do to the Rap industry? It fills the industry with forgetful money makers that do not advance the industry as a whole, all the while holding the real talent down. The industry becomes clogged, forcing Rap enthusiasts to listen through mounds of the same stuff in search of the talent, and the mainstream audience will not listen to the talent because it diverges too much from the formula of catchy beat + lyrics concerning power.
#4: What will happen to the Rap industry? One of two things will happen. The industry will either slowly degrade due to the holding back talent, and will be struck down by a great innovator (such as what Nirvana did to hair metal), or the innovator will change how the genre functions as a whole (as Metallica did to heavy metal).
Either way, Rap as we know it will sadly be gone in the near future. Many UG'ers despise Rap due to it's lack of lyrical content, but they do not understand that the lyrics concern something that is incredibly important to Rap as a culture.
I used to like rap.
Then came catchy beat + lyrics concerning symbols of power.
It isn't a lost cause though. It is a phase.
Eventually, it won't be worth paying for "catchy beat + lyrics concerning symbols of power", everyone will be able to do that themselves.
This forces only true talent to come forward because it is something only a few can do.
Anyway, the way I see it, the music industry works like this: something new, fresh, underground, and innovative becomes popular. At first frowned on, the meme becomes popular - profitable. Then, money is made off of it. The meme becomes oversaturated, overexposed, and a caracature of itself. The meme then dies, and another one is found.
However, it seems Rap is all about 'the capital', like you said. The commercialization, overexposure, and money that killed off every other musical movement has not made Rap into a joke - that was rap's intention. Every other genre had people saying "pssh, sellout bullshit." With Rap, the same circumstances have people saying "pssh, hater, I'm balling, yo."
The lyrics of rap are becoming a tautology and half the beats are original. The music is a joke and half the fans are non-people. I laugh every time I see a white kid dressed as a thug with a John Cena T-shirt on.
However, stay tuned - this touches upon my final blog.
I never really liked rap, as a matter of fact, I hate it. But the old school rap is much better than the new rap. I completely agree with you that rap is slowly degrading. Rap is getting more and more monotonous.