I'd claim things are more nuanced. There are many reasons why UIs in many places, not just cars, suck. In cars, wether warranted or not, there is also pressure from legal to err on the side of building a cludge that is unassailable vs. a smooth user experience that could be grounds for a class action because it doesn't make enough of an effort to discourage dangerous user behavior.
It’s because the incentives are in the wrong place. When the average Joe goes to a car lot a new truck with a touchscreen is “Futuristic” and “Modern”. The only cars that come with buttons are the base models, and are therefore “cheap”.
The car industry isn’t in the business of building great UIs, they’re in the business of selling cars off of the dealer lot, unfortunately.
