> but does Alphabet actually intend Waymo to be a trillion dollar retail car business itself, selling cars to everyone?
Google doesn't do retail other than Chromecast and Pixel phones, and that is already annoying to them as it is because it involves something Google is notoriously bad at - actual customer support.
Starting up a car brand is orders of magnitude worse.
For one, people actually need to trust your brand to survive for at least five to ten years - cars are an investment, and a car that I can't trust to get safety-relevant spare parts (brake rotors, brake pads, axle bearings) all of a sudden is essentially an oversized paperweight. For a company such as Google, this alone (remember Killed By Google) is a huge obstacle to overcome.
Then, you need production. Sure, you can go to Magna or other contract manufacturers, or have an established large brand build vehicles for you, or you say you have to go the Tesla route and build everything from scratch. Either way has associated pros and cons.
And then, you need a nationwide network of spare parts, dealerships, repair shops and technicians that can fix the issues that people will get alone because the wide masses abuse cars in ways you might not even dare think about while testing, or because other people run into your cars and so your cars need repairs.
Even being a derivative of an established car brand can be a royal PITA. Let's take Mercedes Benz as an example with the 2003-2009 Mercedes-Benz SLR McLaren. On paper, it's a Mercedes vehicle, with a lot of the parts actually originating from stock Mercedes cars - but most dealerships will refuse to work on it. Either because they lack the support to even properly jack the car up, or because they lack the specialized tools for the AMG engine, or because they cannot even order the parts as Mercedes gates repairs for that thing to special shops. Or, again Mercedes, with Maybach luxury cars. The situation isn't as bad as with the McLaren, but their cars are challenging in another way - the S 650 Pullman weighs around 3 metric tons empty and is 6.50 meters long. Good luck finding a jack even capable of lifting that beast, most Mercedes sports-car shops don't carry jacks that are normally used to lift Mercedes Vito transporters!
Even Tesla, and they've been at it for the better part of two decades, still struggles with that. Their shitty spare parts logistics actually drive up not just insurance prices for their own customers, but for everyone - hit a Tesla with your Dodge and be at fault, and now your insurance has to pay out for months of a rental car because Tesla can't be arsed to provide the body shop the Tesla ends up at with spare parts in any reasonable time.
Established car brands however have all of that ironed out for many, many decades now. American, Asian, European, doesn't matter. And the spare parts don't even have to be made for cars: ask your local Volkswagen dealer to order a few pieces of "199 398 500 A" and one piece of "199 398 500 B" and you'll probably have a lead time of less than a day, at least in Germany - for the uninitiated: that part number belongs to the famous sausage, the second one to the accompanying curry ketchup, with more sausages being sold each year than actual cars.
And established car brands also bring something to the table: their own experiences with integrating smart technology. Yes, particularly German carmakers are notoriously bad in that regard, but for example Mercedes Benz was the first car brand in the world to get a certified Level 3 system on the road [1] and are now working on a Level 4 certification [2]. That kind of experience in navigating bureaucracy, integration and testing cannot be paid for in money.
tl;dr: I see no way in which Waymo goes to general availability regarding selling cars. They will run their own autonomous car fleets in select markets where they can fully control everything, but seeing Waymo tech generally available will be as part of established car brands.
[1] https://group.mercedes-benz.com/technologie/autonomes-fahren...
[2] https://group.mercedes-benz.com/technologie/autonomes-fahren...