Simple, if you buy a car that's too heavy for the existing infrastructure, you either pay for the improved infrastructure or take the risk yourself. The minivan that I drive the kids in is only 4,300 lb. If you're driving something heavier than that then, best of luck. I expect that if I'm driving a camper, and I fall off the road, I'm just done. Game over.
I don't expect infrastructure to adapt to the minority. That's not what it's for.
At the moment I believe there are minority that's becoming a majority but I maintain that if they're the ones that require the infrastructure the payment for that infrastructure should be built into the cost of the vehicle or the licensure thereof.