I agree, there can still be improvements in many areas. I would say ditch this whole discussion and argue that personal vehicles shouldn't be the primary option and the focus should be on more efficient and effective public transport instead. But on the personal vehicle side, the practical first step is phasing out ICE vehicles, which brings a huge overall improvement to transport efficiency as it stands. The second step would then be making the least efficient EVs more efficient. EV development and design can still progress during that time, but millions of km of roadway is constructed based on this standard shape of vehicle. If you want more efficient than the I6 and M3, I'd say get an electric motorcycle.