Other responder is on the money for established brands.

For new car makes, they are forced to play it safe.

For example Rivian, let’s assume there is no technical constraint. They need to decide how much they are willing to risk before introducing a new product. When you invest billions before the first customer buys anything, your investors who are fronting all that capital want you to use the formula that is proven to work in every respect apart from whatever dimension you’re innovating on.

Cars going on sale this year were designed multiple years ago. They were tested. Tooling and whole new production facilities needed to be designed and built and supply chain set up for all the new parts. Test batches evaluated. It’s not like how you patch shit software almost on the fly in today’s beta culture.

If someone like Rivian got the shape wrong because in the meantime everyone decided the porsche 356 was the prettiest car ever made and every new car was round and curvy, they’d lose what’s called product market fit, which is the death sentence for every failed company. As a car maker they can recoup some money by slashing prices but this whole product cycle would be a huge cash loss they cannot afford to miss.

So everyone plays it safe. Everyone copies apple. Everyone emulates the design direction of Ford’s F150, Toyota’s Prius, etc.