Outside of the premium brand/build quality, I think Tesla was actually a successful proof of concept of what they could have done or could do. Computer/software-powered, battery-charged, integrated hardware/software, principled product tradeoffs, new retail model, advances in charging technology. Big parallels to the first iPhone. You even heard the same complaints from consumers when the first iphone came out ("I want my buttons/physical controls back", "The battery/range dies too quickly"). Apple may not want to be in the car business, but I think Tesla showed that cars could just be computers now