And I suppose farm equipment can be made to run on batteries? NOT. Or semi trucks to bring the groceries, and everything else to your city? NOT. Airplanes? NOT. Ships? NOT (although they could be nuclear or sail, or even oared - anybody up for a job rowing a freighter?).
Why do you think that everything has to be powered by this one, single technology? I don't know if "plug-ins" are part of the answer but if they are, then it would simply mean somewhat less oil used for passenger cars which could then be used to power the semi-trucks, airplanes, etc..
No one's claiming it's the silver bullet, just perhaps a part of the puzzle.
I don't hear any one saying that ALL vehicles should run on electricity. It just wouldn't be feasible. However, there are enough passenger cars on the road, that using electricity for some of them would help reduce gas consumption, and make for cleaner air in the close quarters of cities.