Not all days in Phoenix are sunny and 600 square miles is not "carefully controlled set of streets".
According to https://www.wired.com/story/waymo-google-arizona-phoenix-dri...:
"Once Waymo is up and running in Arizona, it will gradually expand its service area to cover a 600-square mile swath around Phoenix"
By all signs that's going to happen this year.
Not all days in Phoenix are sunny, but only 5% of days are rainy, and 0% are snowy. As compared with many midwestern cities, which get precipitation about a third of days. And all of which have snow, sleet, and ice to deal with much of the year.
The current program says: "We’re searching for early riders in parts of the Phoenix metropolitan area, including Chandler, Tempe, Mesa and Gilbert." So it's definitely not the 600 square miles you claim, and I've seen no evidence that riders can go absolutely anywhere even in the test area. And I note none of the video was at night.
Even the article you cite is clear that this is very limited, and that Waymo is intentionally avoiding disclosing a great deal, including where, when, who, and how much.
Yes, this is very cool. But Waymo, as it should have, has clearly picked the easy place to start. For a domain this complex, the 90/90 rule definitely applies.
“I've come up with a set of rules that describe our reactions to technologies: 1. Anything that is in the world when you’re born is normal and ordinary and is just a natural part of the way the world works. 2. Anything that's invented between when you’re fifteen and thirty-five is new and exciting and revolutionary and you can probably get a career in it. 3. Anything invented after you're thirty-five is against the natural order of things.”
It'll be very interesting to see where it goes. One of the discussions I've had with friends is the extent to which private ownership of cars goes from near-universal to niche. Reactions are all over the map, but my personal bet is that a lot of the kids who grow up with the idea of autonomous cars will never develop that very American attachment to personal car ownership.
That's not shocking at all to me. There's a huge difference between "works well in carefully controlled demo conditions" and "works well enough to replace a mature product". A sunny day in Phoenix on a carefully controlled set of streets is very much the easiest difficulty level of driving.