It's people who aren't paying attention to WTF they're doing that cause the danger, not cars or bikes or pedestrians. The rules of the road (including the rules for cyclists and pedestrians) include tons of redundancy so one party not doing what it should almost never causes accidents.
Take for example a pedestrian and a car turning right arrive at an intersection. The pedestrian has a walk signal and the car wants to make a right on red. Both those actions are triggered by the same condition, no cross traffic. In a naive simulation they'd hit each other. In the real world they see each other and one yields to the other in a manner that depends on the situation.
I walk through a "highly walkable" city to/from work every day. As someone who used to have to drive a delivery vehicle I try not to be an idiot pedestrian, when I cross on a don't cross signal I time it with the lights, I don't cross when someone might want to race through the intersection just before the light change, etc.
The behavior I see from other pedestrians and often cyclists is just moronic (and drivers too but there's so much traffic they rarely have opportunity to do stupid things). I don't expect people to wait for the ok to cross every single time but people should at least make sure their actions don't directly conflict with other traffic (like the difference between a car taking a right on red and straight up running a red). Presumably many of these same people who don't pay more than minimal attention to what they're doing when they're on foot or two wheels will continue to not pay attention to what they're doing when they're driving a car (hopefully they at least take their headphones out).
Making a city walkable is just a politically correct way of saying they're gonna make it harder for idiots to meet at high speed.
> If a driver doesn't have time to slow down and stop for a pedestrian, they are going too fast. It's that simple.
Take your circular logic and shove it up a bodily orifice where it doesn't easily or comfortably fit. If I wanted to get hit by a truck at walking speed all I have to do it time my commute to coincide with when the sun will be on the horizon and cross a particular street when all the lights are red but just before all the right turn arrows turn green. After about a week or two doing that I'd probably get hit.
Every two party accident has at least two parties that could have done something different that would have prevented the accident. Accidents are fairly diverse in their circumstances. Just assigning blame to one party by default is an exercise in bad policy.