Very good point.
Note that the main problem with all electric vehicles is the power mix and cost depends on how electricity is generated.
Electricity in much of the West is from a mix of solar, wind, geothermal, tidal, and hydroelectric power, which result in an e-gallon costing about 1/10th what a gallon of gas costs.
In areas with coal-fired electric we're starting to see (Economics studies) indications of coal and oil increasing in cost, making the comparative costs different and the climate change and pollution impacts also different. However, if you have home and work solar or wind power, you can always trickle charge the battery systems to ensure a near 100 percent green fuel, and since solar costs are dropping fast (cheaper than oil now, competitive with coal) this may change quickly.
Some relatives and friends of mine use all electric or mostly electric cars to - basically - pay nothing in gas (other than an annual gas engine assist "burn" for the mostly electric ones) and as a result "fill up their tanks" with cheap electrons. Even if they add costs for solar charging or buy "green" power mix from the utility (solar/wind/hydro mix) it still works out to around 1/8th the cost of gasoline.