The above link was found in the original discussion board, which is here: https://forums.tesla.com/forum/forums/ac-induction-motor-why

Some key observations:

Batteries can't store AC electricity. One requires power electronics circuitry to convert DC to AC which might involve a trade off. Yet why go for AC motors?

Below are the arguments

- DC motors require rare earth magnets which can add to the weight of the motor which can be expensive & can't be mass produced. They can only be extracted. AC motors require the induction coil which can be easily manufactured. There can be numerous counter arguments to it, but when measured, advantages of AC motors manufacturing will always weigh more than DC.

- AC generators have 3% more efficiency than DC (as mentioned in one comment) during re-generative braking

- High Traction: Max torque at 0 rpm - this is something that only electric vehicles with high traction electric motors can claim. 3 phase AC induction motors have been known to give 100% of their torque as soon as you start them.