Summary: cars depreciate from new towards zero. Only some folks buy brand new and run 'em into the ground. Many more lease then sell on or buy 2nd hand and re-sell later, extracting value. If you put a floor under the price of 2nd hand cars (b/c batteries in such cars have to have useful residual capacity) then you just raised the cost of driving for a large proportion of poorer drivers—unsustainably.
