I don't think this is the biggest reason. It's because most cars now come with always-online LTE modems and everything is software-controlled. Couple that with a product VP who wants to make his bones and you get "turn everything into a continuing revenue stream." Doesn't matter whether the car is electric or ICE.

IOW, they're doing it because they can.

The solutions are:

1. Don't buy these cars.

2. Hack the software and share that knowledge.

3. Install a 50-cent switch to apply power to the seat heaters directly.

4. Disable the goddamned modem and share that knowledge too.