Scaling production isn't the issue for Waymo, it's scaling and maintaining operational capabilities within cities at a cost that still lets them be profitable.
I think it's possible, but it's definitely less trivial than scaling production of more self driving cars.
Those go hand in hand. In theory the successful mass production of their vehicles should drop the cost so that they can turn a profit. The increased number of vehicles and ridership cover the staff to maintain them. As I mentioned elsewhere I would not be surprised if the plush leather seats give way to easily cleaned hard plastic chairs.
No, I'm saying the problem is scaling that's not just building and maintaining the cars themselves, but rather building and maintaining capability around the cars.
I think it's possible, but it's definitely less trivial than scaling production of more self driving cars.