I fully retired from Aviation a couple of years ago but just prior to that I worked on a twin Cessna SIDS and prior to that on a few older single Cessna rebuilds. I would have to say what I saw during those projects was not good.In the twin case we found major problems during the rebuild but not in the areas the SIDS docs covered, in the single cases we saw major wing attach point corrosion as well as other problems. In one case the wiring insulation just fell apart as we moved it for the inspection.
There is no doubt in my mind that somewhere in the future life of these aircraft if the repairs hadn't occurred, then we would have seen one or all falling out of the sky. The fact is that none of you would drive a 1950s car or truck without major mechanical and attention to its structure, yet we seem to think an aircraft is bullet proof just because we want it to be.
One of the reasons for me leaving aviation is that in the end, as a LAME I couldn't see how I could sign this stuff off with 100% certainty that it was OK to the next 100 hourly. I was also tired of arguing with the "penny pinchers" about what needed to be done to their precious toys. These people spent a fortune on the cars but wanted to spend nothing on their aircraft. Every 100 hourly was a battle to get them to agree to comply with ADs etc.
I'm sure that CASA in its normal one size fits all approach has caused problems but there is no doubt in my mind that there was a need to force owners to look very hard at their aging aircraft.
Wunwing