Indeed it is, because only someone without a brain would fail to predict the dramatic rise in the cost of electricity which such an increase in demand would cause. The money you save on gas will be made up by paying more for residential electric rates and the inflationary effects of higher electricity costs across the board.
There's no such thing as a free lunch.
This will be happening regardless.
People are buying these cars and Tesla has produced one a lot of folks would like to own. Tax incentives will probably disappear in the next couple years, by then the cost on the cars will come down, and more manufacturers get on board, like BMW is now.