Comment by chongli

There's another side to that coin. If every restaurant that wants to offer delivery has to have their own driver, that means there are tons of drivers sitting around doing nothing while waiting for orders to come in. By outsourcing delivery to Uber, all restaurants in a city can be served by one pool of drivers, leveraging economies of scale. This opened the door to many more restaurants offering delivery because they didn't need to pay drivers to sit around.