One of the problems with consulting is that it's really hard for most people, while employed, to line up enough work that they can become consultants in the first place. Most people will never get the chance, even if they have the talent, because they can't front the initial financial cost. This keeps a lot of people out of self-employment who would otherwise be a better fit for it.
The Kickstarter-esque idea seems strong, but the biggest problem with this idea is that people who have serious ($150+ per hour) work to offer generally don't solicit on the Internet if they can help it. They prefer to source through word-of-mouth, which is pre-technological and broken and leads to that imbecilic situation where you have to be in to get in... but I don't make the rules.
That's why I haven't pursued it. It's one of those startups that requires fixing people, and any startup that goes long on human nature is facing extremely bad odds.