> The goal here is not to see who is the best under imaginary conditions, it's to determine whether driverless cars are safe in real life as currently deployed.
But the cars are constrained within specific geographic zones. Ignoring anything else, that alone lead to many assumptions that need to be taken into consideration.
This isn't "real world". This is more like open air lab expirement, where some subjects (Waymo) have special constraints. The drivers they're comparing against, don't share the same constraints. You can't draw a generic statement from that, no matter how you twist it.
This is a marketing stunt first and foremost.
Despite the universality of what you cite, driving accidents are likely an 80:20 issue where a small fraction of people cause most of the harm.