Cars much bigger, heavier, and with worse visibility than necessary, make the roads more dangerous for everyone else—motorists, bicyclists, pedestrians, everyone.
The whole thing's turning into an expensive, dangerous game of prisoner's dilemma. It's best if everyone buys exactly as much car as they need, but anyone who "defects" and buys a bigger, heavier car is safer than everyone else, while making everyone else a little less-safe. Iterate for a few decades and you get the current situation.
However, begging individuals to behave differently isn't going to fix the problem. Certainly not in the US.
Oh, for sure. The old-school conservative solution, from back before "conservative" meant "simply don't try to do good things, at all" (at least, in the US) would have been to try to price in the added risk to others (and other externalities, like extra road-wear) to discourage having too-large vehicles. I think that could work.
Never gonna happen, because too many people think discouraging choices that make public roads more dangerous, or simply paying for costs they impose on others through their choices, is outright tyranny, but hey, it's a nice idea.
Please don't go back to posting ideological flamewar comments. It's not what this site is for, and destroys what it is for, and you've mostly been doing a pretty good job of avoiding it (thank you!)
The whole thing's turning into an expensive, dangerous game of prisoner's dilemma. It's best if everyone buys exactly as much car as they need, but anyone who "defects" and buys a bigger, heavier car is safer than everyone else, while making everyone else a little less-safe. Iterate for a few decades and you get the current situation.
However, begging individuals to behave differently isn't going to fix the problem. Certainly not in the US.