Ideally, yes. But it's also a better use of existing public funds versus... whatever the hell they're currently used for. As a taxpayer, I'd just once like to see my money going to something tangible that affects my own life.
Not sure if you've been to LA, but they have been working on expanding the train system in preparation for the Olympics. So they're trying to do both, use the private sector with Waymo, and were already using your tax dollars to expand public transportation. Seems like a win for commuters to me, unless you're an Uber driver.
I actually used to live in L.A., but it was over 10 years ago. They didn't even have a train to the beach at the time because the people in Beverly Hills and Brentwood didn't want the filthy poors going under their fair cities and were blocking it. I hear it's much better now.
We lived in North Hollywood and used to take the train downtown and to Long Beach all the time. They also built the Orange Line in the Valley while I lived there and I thought and still think a very long dedicated bus road instead of a train is silly. Anyway. I'm glad they're improving things.