Yes, I agree - re-tests for everyone every 10 years. As someone has already said, driving /road conditions change over time, also laws applying to driving change over time & I think most of us will admit to drifting into bad driving habits over time.
As an oldie myself, I don't mind driving behind a 20mph oldie but realistically, if they only feel safe driving at that speed, are they really safe at all?
Without trying to be controversial, I think the biggest cause of driving accidents involving the elderly is automatic cars, where, in a moment of panic, the accelerator is pressed instead of the brake. I had my parked car written off by a lady who then went on to smash a park bench (luckily no-one was sitting on it at the time) & demolish a wall - all because she'd pressed the wrong pedal. In same the week my car was demolished, there were two other reports of similar incidents in the local paper. What do other people think?