I don't think any of these things are primary reasons. My guess is it's more about selfish ("fiercely independent") behaviour and what you can get away with, an

I don't think any of these things are primary reasons. My guess is it's more about selfish ("fiercely independent") behaviour and what you can get away with, and a lack of appreciation for rules/regulations that can (on the whole) make for a more reasonable society. The idea that there are fake plates and minimal enforcement seems ridiculous to me. (I'm Australian but have driven tens of thousands of miles in the USA.)