Of course, but I never claimed that they would do that. At some point though other autonomous services will enter the market and Waymo will have to compete with them on price. Even if that doesn't happen (which seems incredibly unlikely), they're still competing against public transit and people driving themselves (or privately owned self driving cars). Not having to pay a driver means the floor where they can make a profit is lower.

If we're in a world where human driven Uber's are $30, you're right that Waymo probably won't charge $20 just to be nice, even if it only costs them $10. They might charge $20 though if their data shows that it would 10x the number of riders or if they're also competing with another autonomous taxi company.