Waymo now generates more than $350M in annual recurring revenue, says https://ideas.darden.virginia.edu/waymo-fully-autonomous-fut..., and quotes $130-150k per car.

So one year of revenue buys ~2500 cars at those prices, which is roughly the size of their fleet (~3000 according to Wikipedia). It seems plausible that newer cars will be cheaper as designs get optimized, economies of scale hit and what used to be really expensive cutting-edge hardware becomes commoditized and goes down in cost over time.

They certainly also need support including contractors that assist cars that get need human input, maintenance etc. and the electricity for the cars isn't free either, but just based on these numbers, it sounds like they are likely close to being profitable if you ignore R&D.

If you assume $10 a ride, and a car giving 3 rides an hour for 12 hours a day, that's $360 in revenue per car per day, close to the $320 you'd get from $350M/3000/365. That means each car pays for itself in about a year (ignoring all other costs, of course).

Based on this and the assumption that cars last for more than 2 years, I'd guess that Waymo is only "unprofitable" (not sure how this works in accounting terms) due to ongoing R&D and expansions and there really isn't much more to "subsidize".