For an ICE vehicle weight reduction makes perfect sense, however for an EV it makes very little difference. This sounds counter intuitive and is probably why not a single EV manufacturer gets it. Not only because it is harder to reduce weight percentage wise from an EV due to the heavy battery.
At continuous speed the energy equals the total of all resistance, like:
air resistance, roll resistance, drive line resistance, motor losses, electrical losses etc.
Weight has no part in this equation, just indirect as it has some influence on the roll resistance.
When accelerating weight does play a big part, however an EV can recover the energy used for accelerating when decelerating. For accelerating/decelerating weight influence is dependent how efficient the regenerative system works. A theoretical 100% efficient regenerative breaking system will recover all energy used for accelerating.
It makes far more sense to focus on other aspects like: aerodynamics, low resistance bearings (air or magnetic), Vacuum motor, extreme high voltage batteries, good thermal insulation of cabin (to save HVAC energy), large solar panels area (a longer vehicle will also improve aerodynamics) and an efficient regenerative breaking system.
And for anyone who does not believe me, explain this:
Difference between a small and a large ICE vehicle is > 300% in fuel efficiency.
Difference between a small and a large EV is < 30% in energy efficiency.
(the 30% can mainly be explained by difference in: frontal area and tire width)