At the end of the day, it really comes down to the weight of the vehicles. There is absolutely zero justification for any standard-use car to weigh more than 3,200 pounds, and that's for a SUV.
More weight affects EVERYTHING.
Material logistics/sourcing/shipping/construction costs and emissions/waste-disposal, end-product shipping/distribution/operating-costs and emissions/repairs/waste-disposal, as well as infrastructure construction/maintenance. That's just hard costs. I could go on in more granular fashion and add soft costs like less traffic and less road noise as well.
I drive a very loaded gasoline powered Fiesta hatchback. It's got cruise control, a great entertainment system with car play, even stupid neon lighting I didn't want. It weighs only 2,600 pounds and even though it isn't fast, I don't have any issues getting up to speed. My mileage is consistently 29 in LA traffic and 34 driving fast on long highway trips. It's nearly 2 feet (22 inches!!) shorter than a Camry and I can park it basically anywhere. Because it weighs so little, tires last forever. It cost me less than $20,000 brand new. My point is that a freaking heavy and large 3,400lb sedan, or 4,500lb SUV is 100% supremely unnecessary.
Multiply hundreds or thousands of weight savings per-car over millions and millions of new cars sold in the US alone would insanely positive and tangential effects on the planet. Eventually those gains would reach the economy and infrastructure too.
It just infuriates me that there is a relatively simple way to mitigate so many issues and it's so blatantly ignored or not even known.