If self-driving works it's inevitable that the market will transform from mostly selling cars to mostly providing robotaxi service.
Robotaxi service has "winner takes most" dynamics, just like regular human-taxi service. Just look at how stable Uber and Lyft marketshare was over the years.
Imagine company X drops 10 thousand robotaxis in San Francisco area. Anyone who cares to can get a taxi for half the price (or less) of regular taxi.
Company Y develops self-driving technology 6 months later. There's just no way for company Y to re-take significant market share in San Francisco if their costs are similar to company X.
They can drop 10 thousand cars but most San Franciscan who want such service already have app for service X installed and a habit of using it.
Company Y might decide on (expensive) marketing campaign or price war but company X can do that as well. Company X can finance price war from profit but company Y must borrow. And there's only so much you can borrow.
In US we saw this with Uber vs Lyft vs everyone else. Early market share of Uber proved to be bullet proof regardless of what Lyft tried to do.
In China Uber was in a trench price warfare with Didi and when they didn't see a way to win, they decided to loose (and sold their business to Didi).
So the winner of robotaxi market will be the first company that has a working self-driving software AND can produce millions of cars per year to capture the market.