Ok we should be solving both problems, I agree, but the reality is agencies and political processes have limited capacity. And how much society and influential people in that society is consumed with one thing, the less they do about the other.

And I would say that I'm not proposing to rework society in sociological sense, but rather to throw out the standard engineering standards and replace them with better standards.

And actually it does matter even in the case you suggest. If a car rolls into an intersection, what speed that car is matters. It matters from what points it is clear that the car is out of control. It matters if there are speed bumps or something along those lines that can send strong signals to a driver.

If you have all raised intersection then the top speed of cars will simply be lower and if somebody human or AI makes a mistake that lead to a crash, that crash will be at far lower speed.

And proper road design also leads to less intelligence and fancy car design being required. I rather get hit by a shitty designed unsafe old car at 20mph then a fancy new car at 30mph.