What I think will be the greatest impediment to Pure EVs is the development of Bio fuels- if Biodiesel from algae and or Cellulosic ethanol becomes economical then the pure EV will need a Eestor like revolution in electrical energy storage to have any chance. Biofuels use existing infrastructure, are domestically sourced, are carbon neutral, and are much less polluting than fossil fuels. Now I was thinking how could I make a competitive pure EV even without the Eestor like technology - this is my answer - like the GM volt I’d give the EV enough rechargeable batteries to go 40 miles on a charge- but instead of an ICE as a range extender I’d use some type of metal-air batteries, these batteries have the advantage of very high energy densities including one that had a higher energy density than gas ,a very long storage life , and are reasonable inexpensive to produce, their disadvantage is that they are not rechargeable they have to act as a fuel cell or as a non-rechargeable battery. So in my mind you’d get an EV that would have a 40 mile range on an overnight charge and the ability to plug in these air-metal batteries to give it a much greater range say 500 extra miles - and an infrastructure to exchange spent batteries for new ones at a price that would approximate gas prices.