Not saying this HAS to happen. But I remember when Ubers were clean, quiet, cheap too. I think you are just looking at a product before the enshittification, when they still have to pretend they care about your comfort.
As I understand it, whatever it costs, is strictly less than the market dynamics of providing the ride today.
There is probably some market equilibrium where they could reasonably provide <5 minute pickups for waymo users that would both cover the cost of the automobile and still be less than the price of an uber today.
It will undoubtedly get enshittifed in its own way, probably higher prices, but at least it will be reliable when booked. Ubers seem to be a crap shoot these days if they're actually going to come and get you.
I can't guarantee that Waymo won't be enshittified, but one fundamental difference with Uber is that Waymo doesn't need to compete in the labor market for drivers. When the low end of the labor market got red hot in 2023-24, that's when Uber prices climbed rapidly because drivers had other options; Waymo won't have this problem. It won't be affected by other things like ever-rising health care costs or local regulations guaranteeing driver wage floors either.