But Waymo and its partners would only just be starting to ramp production of Waymo's specific vehicle model or models.
Ramping to 350k units/year of custom Waymo I-Paces would probably take several years, for example.
Waymo already has a large plant in Detroit that is ready to mass produce robotaxis:
Waymo’s Detroit plant begins outfitting cars with driverless tech
So I don't think it would be that hard for Waymo for ramp up production of robotaxis.
Just scaling up the production of high-resolution, long-range, automotive-grade lidar to 100k+ units per year could take several years.
I am not aware of any evidence that scaling up production of high res, long range, automative-grade lidar would take years. The biggest problem is lack of demand. There aren't enough companies demanding high res lidar for it to be profitable yet. It's why these lidar start ups are struggling.