It’s a tough question. My DF eventually stopped driving at 92, following a minor bump. It was heartbreaking when he brought me his car and handed over the keys - he felt all his independence had gone.
Personally I wouldn’t mind taking (at my own expense) some sort of driving assessment from 70+, but think it should be just that, an assessment and should result in certain recommendations, but not actually remove a licence, except in extreme circumstances. As others have said, health can vary from day to day, ‘nerves’ creep in too if it’s very important to an individual to have their licence. My family say I’m a pretty good driver, but I can’t parallel park for toffee!
Couldn’t when I was 17, never mind 70 - just lucky on the day of my test!