My back of the envelope calcs say that if batteries energy density increases by 30-50% the weight penalty for electric cars disappears. It's a fuzzy line because it depends on the cars range.
Difference between electric and gasoline cars. With a gas car the marginal cost of extra range is low. With electric it's high. With gas cars the marginal cost of extra HP is high where with electric it's low.
Difference between electric and gasoline cars. With a gas car the marginal cost of extra range is low. With electric it's high. With gas cars the marginal cost of extra HP is high where with electric it's low.