Uber and Lyft calculate that their cooperation doesn't affect Waymo's trajectory too much, and they immediately benefit from "more drivers."

> Or is the idea that Waymo becomes a hardware provider and uber / lyft become operators?

This is one natural way that things may shake out and a natural path to scale. But Waymo needs to have a fallback plan of A) other parties to work with, or B) just doing it themselves to get a good deal with Uber/Lyft in the long term.

Uber/Lyft would like Waymo to not the the sole provider of autonomous technology and to work with them; they can expect to receive rides at just a bit above marginal cost in that case.