Yes, seems like this can be viewed as adding a sub-brand, not a brand change. Like Amazon Prime and Amazon AWS are both sub-brands of Amazon.

One could speculate they're planning ahead, making space for another brand, either a different variation of SDC as a service or some other type of product.

Maybe they'll have SDCs with multiple riders (like Uber Pool) and call it Waymo Share. Or maybe they'll have self-driving commuter buses (like Chariot) and call it Waymo Shuttle.

Once you've mastered SDCs, there are just so many applications that you almost expect to do multiple things with it. They could license to car manufacturers and call that WaymOEM, sell their own cars and call it Waymotors, do trucks and call it Waymo Freight, etc., etc.