What's wrong with demanding higher standards of driving?
I'd have happily retaken my driving tests after 20 years or so. But no, I've been driving 36 years already, and can do another 16 years before my current licence expires; and even then there's not really any hoops to jump through to renew my licence - I find that ridiculous.
Resting is an opportunity to check:
a) eyesight
b) reaction time
c) hazard perception
d) knowledge of the HC
e) driving ability
And since anyone being retested is by definition an experienced driver, I'd make the retests harder than the normal test.
The people being retested of course. Would you expect your periodic motor insurance renewal to be free? or your MoT, or your drivers licence? Or your passport?
Retests would also include a retinal scan for uniqueness; no more paying someone to take a test for you.
And there's the issue - insufficient capacity in the system. But charge people for retesting, and increase enforcement (particularly automated enforcement) and plough the money into adding capacity to a system that desperately needs more capacity.
Ramp up retesting gradually - I'd probably start with those who are caught flouting certain road traffic act offences, then consider age groupings.
Poor driving at any age should be addressed, no argument there.
Speed and inattention are my biggest concerns on the road. Flood the roads with AI cameras that detect: the driver's face, instantaneous and average speed, tailgating, middle/fast lane hogging, red-light jumping, etc. Increase visibility of traffic police (another thing that could only be increased slowly).
Make it self-financing.
Also consider limitations on power, number of passengers that can be carried, permitted insurance groups, and even hours of day when driving is permitted. Have a sliding scale of what/when/how people can drive, not just focus on age.
There you go, lots of ways to manage various risks as presented by all ages of drivers.
God that was long-winded.