Even the big developers cut corners — witness the spate of lawsuits that usually show up a few years after a condo conversion. What makes you think that Zillow will be any better? You’ll have someone in an office trying to hire talent 1000 miles away. Without someone to watch over the circus, how do we know that even licensed people aren’t hiring sketchy subcontractors?
Small renovators generally hire licensed contractors because they can get local recommendations for good people to hire.