You agree there is a systemic problem and then… … You say it’s an individual one?

Intrinsically, yes. We don't naturally have the same natural ability to judge our risk compared to, for example, running on uneven ground. The argument that the only reason people speed is because the roads feel like they can go that fast is often brought out, and is one that needs to be debunked. There are many cases where road design contributes to speeding, like stroads where you have a 4x 4m wide lanes in areas that shouldn't have that much traffic, but generally if you narrow the road to a degree that controls speeding by itself (Typically <3m) you increase risk of accidents, as well as make travel difficult for large vehicles like transport trucks. Narrowing that much is applicable for residential only areas, but not any roads larger than that. Using our 'feeling' of what speed we can drive safely at is NOT a good measure for what speed we can actually travel safely at.

People are largely driving with the instincts they learned with training and over time. They’re not actively thinking about the decisions they make most of the time. We can call that a personal failing all we want but that won’t change the result.

Thats the problem. If you're okay with getting behind the wheel of a 2 ton+ vehicle while not actively thinking about your decisions you shouldn't be getting behind the wheel. You're a danger to yourself and those around you. If you kill or seriously injure someone while doing that, you don't get to shrug off your responsibility and say 'not my fault, I wasn't given an opportunity to improve' or 'I'm driving how I was taught!'. As an adult, you have a responsibility not to hurt those around you, regardless of how good or bad your parents were at teaching you. Instincts alone are in no way sufficient for driving.

I think we should be having regular driving exams (~5 years), and subsidize drivers ed for all new drivers, but I can't make the laws, and most people are against that. Systemic change is great, but until that change occurs, the onus is on the individual to be responsible, especially when its something that has such power to wreck lives.