As far as energy storage tech: you’re forgetting about hydrogen, either to power an internal combustion engine, or to run fuel cells. You’re also supposing that we need most cars/trucks to have a range of > 100 miles. We already have electric vehicles essentially with unlimited range: trains.
If we offload most goods and medium-distance personal transport onto highly automated trains, and have vehicle rental easily available at the endpoints (think Zipcar), we could make do with 100 mile range electric cars.
As far as 50+ mpg 3000+ lb cars, Prius is close to 3000 lb and gets about 50 mpg, no? Besides, with improved crash avoidance and CAD tech, who says that cars NEED to be over 3000 lb. It’s perfectly possible to build a 4-door that weighs 2500 lb, think Honda Fit.
