My unscientific pet theory is that poorly built/zoned neighborhoods and cities, designed as if every human needs to drive a giant car at all times, are to blame more

Neighborhoods are built slower than cars are, and the increase in car size has outpaced construction. Sure we should fix our neighborhoods, but they're not the main reason behind increasing car sizes.

They weren't "poorly written" as much as "lawmakers accepted bribes to add exemptions for semis"