The point is that simply lowering speed limits as the primary lever to improve quality of life isn’t useful. It does nothing to reallocate that space in a beneficial way.
I’m literally arguing in favor of reducing space for cars for more pedestrian, cycling and transit infrastructure
The bottom line is that if you build to accommodate cars, you will never have walkability. It’s geometrically impossible.
Guess what? The city is already built. I agree with you.
The question is how to move forward and slapping lower speed limits on everything isn’t the solution. You need to actually spend money on revamping the infrastructure so there are meaningful alternatives. Try to read more and jump to conclusions less.