One Apple employee acknowledged that in their discussions with Uber employees about their need to pay a commission on IAPs, Uber tried to convince Apple to remove their commission because that 30% would have to get passed on to customers.

However, I have no reason to believe that Uber would actually follow through. It seemed like a bluff. Certainly, any economic theory I'm aware of would have Uber and customers split that 30%, with Uber paying the vast majority out of profits.