Through my interaction with startups over the past few months, I realized that the later-stage startups are not hiring freelancers. Early stage ones are hiring freelancers (especially in UI/Usability field) due to the limited supply, but early stage (self-funded) startups don't have enough dough.
It's an interesting problem because those who need the service the most (in the first iterations of their products) are the ones who can afford it the least.