It's not. Even the worst, dirtiest coal plant is going to be more efficient than your car engine, since it converts much more of the energy (given of as heat) into electricity. Economies of scale definitely apply to power plants.
Gas powered motors are still less brittle than grid-powered ones - it'd be tough to power a military force on grid power for example, but at that scale we should be using local fission powerplants anyway (ie, nuke subs).
[1] http://en.wikipedia.org/wiki/Energy_returned_on_energy_inves...
TLDR: Electric vehicles still win, but only just barely when you include the battery manufacturing costs.
The paragraph on that page that mentions batteries is not at all rigorous - it doesn't attempt to be. The statement "It could be predicted that most Priuses will be junked at age 10 years" strikes me as pretty contentious.