Waymo has been doing public rides (2015) since before either company was founded (2016). Pony.ai also got their permit suspended twice in California for different safety-related reasons, so the comparison says more about the different regulatory environment in China than it does about their relative maturity.
Waymo was not doing public rides in 2015. It was invite only and you had to sign an NDA
They were doing rides for members of the public. That's a public ride.
No, public means accessible to the ~whole public, not a tiny subset.
Invite-only is quite literally the opposite of public. It's private.
With zero public releases/data on crash information.