If they really aren't adding enough value relative to what they extract, then they are opening up a competitive weakness that eventually should be exploited by a new entrant in the marketplace. Right now, the whole area is being opened up by these intermediaries, which are spending enormous amounts on marketing/advertising/promotion to increase customer awareness of the offering and to establish relationships with restaurants. Once this market is developed, a new entrant with a comparable offering but much lower take rate could make sense-- so long as they are very efficient and low cost in providing this service. The fact that DoorDash is making zero/negative profit now suggests that they aren't taking too much of the pie. If they were, they simply wouldn't be able to recruit couriers once the word was out that it was a bad deal.