I’m a cyclist and disagree, given most urban bike vs car crashes happen way below 30 mph changing the speed limit won’t make a difference.

What would make a difference is teaching people to cycle on the road confidently and correctly (eg taking the full lane when required) and also adding a cycling component to learning to drive to give drivers more empathy for cyclists.

Both of these are too big to tackle so instead the solution is to blame speed and treat people like children.