The law of the internet is simple: either you do something I can't do myself (or get from someone else), or I pay you less than you'd like.
Why else would it be any other way?
Twenty years ago, self-publishing a record was difficult and expensive. A big label could get you shelf space at Tower easily, you couldn't. A big label could pay for a recording session with available capital, but it was difficult for you to find the money or take the risk. A big label could reach the dozens of music reviewers, and do it with credibility. Hard for you to do that yourself.
Now when someone comes to a successful musician and says, "we'll take 90% and you do all the work," they're opening the door to an uncomfortable conversation. The label has no assets, just desire. That's great, but that's exactly what the musician has, and giving up so much pie (and control over his destiny) hardly seems like a fair trade.
Multiply this by a thousand industries and a billion freelancers and you come to one inescapable conclusion: be better, be different or be cheaper. And the last is no fun.