Yes, but what will they be powered by?

not sure why you're so confident of that when we don't even produce enough power for our current needs let alone powering millions of cars

How much more generation do we actually need. For one, charging typically does not happen when the grid is at peak load, so a lot of spare capacity is available. Second, it takes approximately the same amount of energy to refine a tank of gasoline as it does to completely charge an EV, so it'll be a wash.