That’s a feeling, not a lack of safety. Intimidating people into buying big cars on purpose is still vile, but the people who cave are giving in to irrationality and putting their feelings above the safety of their kids and of others. Tragedy of the commons is when defecting improves your utility. The SUV/emotional support truck arms race is only decreases the utility of others in exchange for feelings of power.
The feeling of power and safety, itself, has utility. Feelings matter.
No argument that there’s been an active propaganda campaign to make people in smaller cars feel less safe, but propaganda works. You can’t just dismiss it.
I can object to it being used to justify killing kids for a feeling though. Which is what you were doing by suggesting it’s a prisoner’s dilemma.
Object all you like? It doesn’t change the actual reality of what is happening and why people drive murder machines.
Which does not override the lack of safety of a tall heavy vehicle. Small cars are not less safe than emotional support trucks and full sized SUVs, because the latter get specific exemptions from safety regulations.
“I’m going to increase the probability of killing my kid, innocent hystanders because of this one specific critereon i’ve cherry picked” is an emotional argument.