It's not quite as black and white.

The way to sustainability is straight up less cars. No matter what form of car, it's far less sustainable than trains.

Elon is doing a lot for EVs which is a good step. Cars will remain relevant and those cars should be sustainable. But he also opposes rail, in the classic car manufacturer manner. That reliance on cars is good for business but very bad for the environment. EVs are more sustainable than fossil cars. They aren't neutral and also cause other environmental damage besides emissions.

Also, the valuation really wasn't in any way correlated to the production and sale of EVs. Even today Tesla is valued significantly above the competition. Shorting hype and bursting bubbles is normal and good for the economy. The earlier the better. Both for the economy as a whole but also for the company in question. Bubbles will burst eventually. The bigger, the more harmful it's gonna be. Desperate companies aren't good and don't have a history of caring about anything but solving their problems. Especially not caring about environment.

The value can keep growing slowly over time. At which point the shorters will be the suckers. But the valuation timeline really is wild and not explainable by the underlying performance.