You're competing on price, and drivers can use all services at the same time. If a driver gets more of the cut from another service they'll use that too - then they'll of course preference requests from the service that pays them more. It just snowballs - there isn't enough friction associated with switching services as a customer or as a driver to prevent competition on price point until the margins are razor, and then you're McDonalds. Which is fine, but you can't assume current margins.