[serialk11r]

Magnet-less SRMs put more demand on the controller. You lose cost in the motor in exchange for more cost in the controller. Torque ripple (lots of noise, think vacuum cleaner, hand dryer) is probably unacceptable to most car owners.

Elon's idea of using induction motors was actually pretty brilliant, since they have good efficiency at low load + high speed, allowing efficient cruising on flat land despite the motor running at a high fraction of its mechanical rpm limit. A permanent magnet motor geared taller to run at a lower speed is more efficient but the transmission costs more money and needs careful design to not lose efficiency with multiple gears.