there's a magic crossover point where cost-per-kwh for batteries gets low enough that it's cheaper to build an electric car than a gas car. There's some evidence that we've crossed that line in the last few months - now there's a bottleneck of how many batteries can be produced to meet demand - but that's changing fast, too. The transition is going to be faster than people expect.
The way car manufacturers are pumping out BEVs and PHEVs with 50+ km range, and buyers are gobbling them up, I think that nut is showing serious fissures ;-)
Personally, I'm expecting to reduce fuel spending by about 80 or 90% ...