Efficiency is critical for the success of any electric car, and will continue to be for a long time. The reason being that batteries are only just beyond the cusp of being viable for cars in terms of cost, weight and volume.
Most established carmakers haven't yet realized (in terms of adapting their engineering) that this, combined with the very high conversion efficiency of electric motors, means that electric cars get much greater advantages from efficiency improvements than ICE cars do. Single-digit improvements to efficiency in motors, inverters/power electronics and aerodynamics/roll resistance translate almost directly to single-digit improvements in range. And hence also allow smaller batteries, cheaper construction, lighter construction, which again allows a smaller battery.
You can see this very clearly in Audi and Jaguar's models, that have significantly lower range than Tesla's cars for each kWh of battery capacity.
