are being operated for decades beyond their notional design lives
Find me a GA manufacturer that will declare what the design life is. And by the way, how old was Caribou when it was retired?
have modest or otherwise no manufacturer’s support arrangements
I don't even know what this means. But I can tell you that our 30+ year old aeroplane has better parts support than a 1 YO Toyota
do not have fatigue or usage profiles as guidance by which to manage them
Once again, I don't know what this means. It sounds to me like trying to apply airline concepts to GA. Most GA aircraft are overdesigned compared with RPT aircraft because of scale factors (ie its easier to use a 2mm piece of material rather than the 0.9mm piece of material dictated by design calcs). SHOW ME THE DATA that demonstrates this is a problem!!! Its only an issue in the hypothetical world of public service board rooms filled with non-aviation attendees.
receive no more than a yearly/100 hourly inspection that is generic in nature.
This would be CASA schedule 5. Just remind me again who created it and declared it to be adequate?
And we are paying this guy? No wonder we need a Cypress style deposits tax.