One problem is that many of these startups are offering very paltry "bounty's" for the work that needs to be done. I'm happy to offer discounts off normal market prices for this work, but people still need to be prepared to pay for quality.
Another problem is that many of them seem pretty sketchy and no-one wants an association with a company which took the money and ran on their resume.
While no-one's going to get up in arms about someone designing a logo for a company which disappears overnight, a lot of mud is going to stick to anyone who actively markets any business which later turns out to be a scam.