I have zero insight into their pricing mechanism, but I was getting in the car coming back from, no exaggeration, one of the most expensive cities on the planet and so if I was Waymo I would probably price that ride pretty aggressively based on the location alone. Then you throw in all the other data points Google has about its users and I had my first "fuck me" moment where dynamic pricing really slapped me in the face (I've seen it firsthand with the airlines but Waymo is particularly insidious because of the use of my Google history).
And of course I'm aware Waymo has to price high while they're fleet-constrained or folks are going to be waiting forever for a car, but I hope they don't get too content with the absurd margin at $10+/mile. They will be tempted to do just that and so instead of flooding the market with fleet decide they'll put just enough cars in service to maximize profit instead of going for market share (of all riders I mean). But I fear that's exactly what's going to happen until there's credible competition.