They are not. SFO, owned by the city of SF and at the behest of city officials, have been notorious in blocking Waymo: https://missionlocal.org/2023/11/waymo-rebuffed-by-sfo-sf-gu...

Which is strange. You'd think officals would be jumping at the chance to bilk Google out of money that they can line their pockets with.

i've struggled to get an uber for some early morning flights and can see it being easier to waymo to millbrae bart and connect to SFO than waiting a long time or paying insane surge prices for uber

You could also waymo to millbrae and uber to SFO. The price ($5.20) for BART to SFO makes it unattractive, especially since you often have to wait for a while. I've caltrained to millbrae and taken uber to SFO for $12, which is often worth the time tradeoff for me.