In towns or anywhere with good power infrastucture and secure charging points, I think electric cars will make progress. For long distance use they will always have a problem meaning diesels and petrols will be around for a long time yet.
You can fit a large capacity battery but a 70KWH is about as big as the average home wiring will cope with I mean without compromising the supply for heaters fridge and everything else we use electricity for.
70KWH at 240 volts would need 280 Amps to charge in one hour so even if the battery could cope, topping up the tank on a motorway break isnt going to happen. Overnight at home it would need at least 10 hours pulling 30Amps from the meter. What happens to the infrastructure when the whole street is doing that every night?