Highway speeds are worst case scenario so maybe you're right but I doubt it.
Your charge rate acceptance number is surprising to me, I've never seen anything like this in my years of experience designing EV batteries. Preconditioning helps extreme fast charging but isn't necessary for 1-2 C charges at all unless it's very cold out.
There's some caveats to this depending on the exact chemistry but if anything the newer semi solid state NMC cells are even less dependent on this and can charge down to -20C.
EV battery engineer here. It's not hard. Battery management systems are often over engineered but the state of the art is fairly straightforward and will allow battery packs of sufficient size last 200k miles or more easily.
I highly doubt it's true. I can usually approach the same speed in C if I'm working with a familiar compiler. Sometimes I can do significantly better in assembly but it's rare.
I work on bare metal embedded systems though, so maybe there's some nuance when working with bigger OS libs?
But it's not cheaper. And the car companies make money off aftermarket parts. QA just moves to software, so you're not saving anything there either. Plus so far, screens are less reliable than analog controls, so instead of replacing a cheap knob, you're replacing a top quality screen with special manufacturing requirements due to the environment of the car cabin.