Probably true, but these companies will be among the first to deploy; no need to measure against general "widespread deployment". There are autonomous taxis already, albeit not quite yet in the wild.
In my city there are many small streets with bad traffic and environment, that at least once a week I need to verbally negotiate with other drivers who goes first and who goes back. If all cars are autonomous, they may negotiate that; But if only half are, I don't see how this will work.
Most US cities have the benefit of being built for cars; But most European cities do not; and even in the NYC, there are weird small streets that often require negotiation among drivers.
[0] http://www.mass.gov/courts/selfhelp/tickets/jaywalking.html
People are underestimating how game changing "mostly working" self driving cars are.