I also believe that there should be no federally mandated retirement age for anything.
There certainly isn't for FAA inspectors....I personally know several who are past age 70.
Do they still do their jobs OK?
You bet....mostly giving malcontent First Officers, who are just chomping at the bit to upgrade...a hard time.
This is called....turning the screws, ever so slowly.
Younger guys will just have to learn, sooner or later...in the airline business pointy end, the older guys rule the roost, and this is not likely to change anytime soon.
However, there is a bright spot on the horizon...in the form massive retirements in the next few years (USA, anyway), which will have a direct positive impact for the 'disadvantaged'
copilots.