Surely the speed limit is for all road users. It would make no sense for bikes, electric scooters, horses, and mobility scooters to be crashing through at higher speeds. That would defeat the whole objective - to slow down traffic.
There is the concept that roads are shared spaces, and that users should interact more and the result is less accidents. In some places slow speeds h@ve been introduced and all road markings have been erased - no white lines down the middle of the roads, no crossings, no humps, no traffic lights.
https://www.pps.org/article/hans-monderman