ICE are not at pinnacle efficiency. They can run more efficient. They can run clean. They don’t because money and profits. You can’t just decide that battery technology will become so much better. There is a limit to materials and the economics implementation. Energy density,(reply>), It's not money and profit. Engines run at below max efficiency to minimize emissions.<br>That was the reason for the Volkswagen scandal, to test emissions the engine runs below efficiency, but in road driving it starts to run leaner to save fuel at the cost of more NOx.