Automated marketplaces are generally really efficient, which means that they drive the end-user cost down until it meets the cost of supply (ie. they drive the profit for suppliers down to zero). This is what's happening with Uber, even with their subsidised ride prices. (And for a virtual example, this is what happened in the Diablo 3 auction house, and basically killed the 'grind bosses for upgrades' endgame until they removed it.)