Hybrids use the wasted energy that would have otherwise been dissipated in heat in the brake pads and drums to recharge the batteries thereby improving the efficiency. The hybrid is all petroleum powered. Just more efficient.
An all electric, on the other hand.
More efficient at a particular moment in time. There is a lot of other baggage in the background, such as manufacturing, and wear and tear. The motor in most cars these days are good for 200k miles. What last’s 200k miles on a hybrid? Certainly not the battery.
The only thing I envision that will change the equation will be a coating or other product that will turn heat directly into electricity. That, will be the game changer, not storage.