Who says the self-driving car has to be electric? The two things are not dependent on each other.
Less pollution? Not if they keep burning fossil fuels to make the electricity.
And... lithium and cobalt are two things that the U.S. does not have a lot of. We could maybe find some here and mine it. But, I guarantee the greenies would want to stop that mining for some damn reason. So we are back to importing a scarce commodity from countries who are not necessarily our "friends". Not a good basket to put all your eggs in.