agreed. This is also why I said 'culture', not rules. Germans and really most Europeans and even most countries have more vigorous driver training than the US. But 'we' and I'm mostly describing big metro areas in the US have tons of drivers that are resentful of people driving at the speed limit or '5 over'. It's an aggressive driving culture and I don't just mean speed.
My son and I were recently driving from Stuttgard to Munich and he really wanted to open it up so we were going 200-225kph whenever traffic allowed. That's about the functional limit on the 2 lane highways because drivers going 125kph that need to pass slower drivers can't really accomodate much faster coming up behind them and you as the fast driver have to keep your heavy breaking at a reasonble limit. So they merge over and back very reasonably and we are doing our best to 'fit in'. Occasionally someone with a legitimate sports car comes up behind going 250kph+ and we merge over without complaint. They DO NOT pass on the right (unless they are Americans in a rental...). We then see them have to slow down for the slower drivers ahead... which they do without any road rage. It's all very well understood to do your best and let the fast car behind you pass on the left and not get upset or even stressed out and also if you're the fast driver you don't lay on your horn and get grumpy. It's all culture.
As Americans that are in that area a lot ( visiting family ), I've trained my son to drive there. He's widely consider to be like a 'pro driver' amoung his friends at home because he's driven the autobahn and looks like he belongs. He got some Nurburgring laps on him for a birthday present. He's been trained to be a good driver not just good at driving. His friends have 4 hours with an old man trying to convince them to use a blinker....
Dramatically improving driver training would be a really obvious step in my mind. I'd like to say that my son is especially tallented but really, he's just been taught/trained a skill and he's unique among his peers which is really sad.
Back to California.... passing a 10 minute driving test and 25 questions to get a license is a pretty straight forward cause and effect for terrible driving culture in my view.