Yes and no. BEVs are fundamentally simpler than ICE, so one would expect them to be cheaper... after manufacturing was scaled.

Tesla's biggest achievement on the pricing front was creating a viable scaling pathway.

Although it's debatable that BYD wouldn't have done it absent Tesla, because of Chinese market incentives.

Their biggest achievement is showing electric cars work and people will pay for them, and building a charging network that works really well, and neither with any useful prior art to rely on. Even if they go under tomorrow, every electric car is their legacy.

It's overattributing to imagine electric cars wouldn't have become popular absent Tesla.

Climate change would have still been discussed. The Paris Agreement would have still happened. China would have looked at its lack of long term oil reserves and pushed to shift away from non-essential consumption.

There are too many incentives to develop a mass market model, so if not Tesla then someone else.