Most of the costs of manufacture are fixed or at most scale linear with mass, so the range of costs to mfgr the smallest commuter car vs the hugest truck are, at most, perhaps 3 to 1 but more realistically 2 to 1.
"The market will bear" a consumer paying 5 to 10 times as much for the largest fanciest SUV or pickup truck vs the smallest cheapest commuter car. Therefore the profit is VASTLY higher on larger cars and there's an immense motivation to get as many customers as possible into the biggest cars. If you can get a customer to pay 6 times as much for a SUV that costs 3 times as much to make, that's a huge profit lost if the customer is permitted to buy the commuter car.
Another way to phrase it is if almost all your profit comes from selling giant cars, then the customer experience of buying a small car is always going to be awful.
The people buying the largest vehicles are not concerned by cost, so increasing the cost of large vehicles via taxes or fees or regulation only makes the situation worse. You'd like to think that a 20% surcharge on large cars would result in fewer large cars sold, but the guy buying them is a general contractor and he needs the pickup truck to make money so he's just going to pass the cost on to real estate inflation and the extra 20% is going to motivate the dealership even harder to only sell expensive cars.
"The market will bear" a consumer paying 5 to 10 times as much for the largest fanciest SUV or pickup truck vs the smallest cheapest commuter car. Therefore the profit is VASTLY higher on larger cars and there's an immense motivation to get as many customers as possible into the biggest cars. If you can get a customer to pay 6 times as much for a SUV that costs 3 times as much to make, that's a huge profit lost if the customer is permitted to buy the commuter car.
Another way to phrase it is if almost all your profit comes from selling giant cars, then the customer experience of buying a small car is always going to be awful.
The people buying the largest vehicles are not concerned by cost, so increasing the cost of large vehicles via taxes or fees or regulation only makes the situation worse. You'd like to think that a 20% surcharge on large cars would result in fewer large cars sold, but the guy buying them is a general contractor and he needs the pickup truck to make money so he's just going to pass the cost on to real estate inflation and the extra 20% is going to motivate the dealership even harder to only sell expensive cars.