Replicating Uber is hard because it's a 2 sided market - you need to convince both users and drivers to sign up and neither will if the other isn't there alread

Replicating Uber is hard because it's a 2 sided market - you need to convince both users and drivers to sign up and neither will if the other isn't there already. But that's not a problem for Waymo because they control the driving side. They simply need to get users to sign up. When you have something unique and useful, people will sign up.