Oh really. You do realize they have mad significant changes to battery systems for phones for over a decade now. The air power was not a battery system but a charging mechanism that was extremely ambitious and no one else has been able to make it work either. There are hundreds of products that never make the light of day because of Apple internal requirements, but they almost never announce them so early in the process. In fact you can count on one hand the number of times they mentioned a product before it was ready to ship. In most of those it was because they were either going to need regulatory clearances or more
developers to jump in early.
You're not getting it. If Apple underestimated the overheating issue of AirPower, what makes you think thermal issues in a giant battery pack of a moving car is easier to solve?
A phone can be dropped and nothing will explode. A car with a battery pack can crash and burst into flames. Not the same comparison.