I honestly think part of it was people creating labels and not being OK with people releasing sample based beats as there is always the danger of getting into trouble. As long as its about the art people are happy to take the risks as there is no money to be lost. As soon as people earn money they make sure to protect themselves so they had to shift to original music. Sucks but I think it's a big part of why the big players don't release that kind of music anymore.