Agreed over 70s are safer than younger drivers, but consider young drivers in most jurisdictions face restrictions while elderly drivers do not.

Further I’d say anecdotally that past a certain point, certainly by 80s, elderly drivers are not accident free. It’s that they have an increasing number of small accidents until someone takes away the keys. If they do not have someone in their life to do that it’s probably reasonable that the government make that determination.

At some point the reduced vision and reflex speed makes them too hazardous on the road to others, even if they are driving slowly and carefully. Parking lot accidents, hitting kids, slamming the gas instead of the brakes, etc.