Well, first of all I'm talking about AlphaZero, not AlphaGo. And I don't think that's the right way to think about it. AlphaZero created no data, just became a better player. There was nothing it created that could be used for training or verification.AlphaGo worked by CREATING the data it needed.
I don't think it can be ruled out that somebody might be able to do so. The AI would control all independent actors in the simulation, thus playing itself. The rules, like Go, can be fairly simple: get to your destination quickly, safely (for everybody), and comfortably. The huge complexity is in the environment, even before you get to the edge cases: it's no simple grid. And the cadence of moves is not simple either.So if you think you can design a simulator that can create random detailed traffic situations and randomly learn success from "playing" those random traffic situations, then I suppose yeah, you've created something comparable to AlphaGo that can learn to drive.