Waymo's software has crossed multiple generations of sensors and vehicles over almost two decades. It does not seem to be tightly coupled to a particular device.
Not tightly coupled in obvious ways, but as I understand it they aren’t putting it on pickup trucks, convertibles, or anything toeing a boat etc. Their vehicles don’t have aftermarket suspension systems dramatically changing handling characteristics, or turned one into a stretched limo etc.
Which means the software can safely assume the vehicle will behave within a relatively narrow operating range.
I don't think the vehicle performance really matters in the typical case. They're using like 20% of what the vehicle "can" do. They're probably hedging against the long tail of variance on the road somehow. Kinda like how private people can tow whatever the f they want with their pickups but in a work setting you need to keep it fairly stupid proof.
I suppose owners will be motivated to have the thing do the driving (and so seek defeat devices and such), but at least the software can have "do nothing" as a safety mode if it manages to detect that the vehicle is not configured as expected.
And maybe the software can be designed to be coupled to a vehicle dynamics model that can be updated.
The new (as of now than a year ago) Waymo cars still had human safety drivers last I saw one (a month or two ago). I also don't see them taking customers. So they do seem to slow roll hardware rollouts.
