I'm sure electric cars are being, and will continue to be, stolen, parted out, etc. But battery theft won't look quite like catalytic converter theft as batteries are much heavier and aren't as easily accessible. Check out the video of a catalytic converter theft posted by another commenter in this thread [0]. The thief slides under the SUV at the 1:37 mark, does some cutting from about 2:00-2:14, then slides out with his prize around 2:24. In and out in less than a minute - no need to jack up the vehicle (SUVs and trucks are often already high enough), no need to enter the vehicle. And the catalytic converter weighs something like 10 pounds so he can just walk away with it. Stealing an 800-pound battery pack out of a Tesla would be a much more involved operation.

0: https://www.youtube.com/watch?v=EP3N4RwHd5k