This is assuming that all artists are created equally in regards to their ability to self-promote. Trust me, they aren't and it's a problem because some of the most talented and deserving of attention are the most introverted. This is why the "middle-men" actually have some validity. Some people need a publicist, a manager etc to take care of that which is both foreign to the artist and often terrifying.

Dave Heckman seems to think think labels' (or at least his label's) bigger role now is financing bands:

I do think record labels, depending on how this transition turns out, might disappear entirely, 5 or 10 years down the road. We still have exposure, distribution, we provide a level of professionalism. Unfortunately I feel more like a banker than a record label at this point. For example, I’m talking to Skinny Puppy right now, that shouldn’t be a surprise. These bands need the 10 or 15 thousand up front, for production, or the Birthday Massacre might need it to live while they record their new album. Unfortunately on the level I’m at, and moreso for majors it’s being a banker. An artist can’t go to a bank. I have a record label, a back catalogue and a certain amount of cash flow. Now a lot of that goes to pay royalties and mechanicals [mechanical reproduction rights - ed.}, but I can pay advances for bands. Part of what a record label has become is a bank.

and that's not a role there's a readymade replacement for. Bands that can fund themselves through Kickstarter already have a following.