Getting into underground hip-hop is a good way to learn a lot about how big the world is, and how insignificant your views on it truly are. The fact is, no matter how strong your passion for the mellifluous rhymes of MC Throwback Freestyle King or the eccentricities of Kool Keith, your values aren't necessarily the ones the wider world needs to understand.
Sure, the industry is a corrupt, dishonest place. Bloggers are bribed, radio stations receive payola, and the little guy can't catch a break. But in order to be a truly popular artist, it is a fact that the music will need to appeal to a large, diverse audience. A good judge of whether your favorite rapper qualifies is to remember that the world isn't made up entirely of men, that it isn't made up entirely of fans of Golden Age Hip-Hop, and that being weird for the sake of being weird is setting oneself up to fail from jump.
When a label signs an artist, they're taking a gamble on a positive return on investment; the only motive is profit. They have zero interest in holding back your art-damaged instrumental trip-hop trio if they think they can make a buck off of it. Prove to them that they're wrong.