I wish to believe that. I'd expect it of good engineers.
However, I don't trust systems to remain as robust as initially designed, after decades of undergoing constant pressure to reduce costs, make things more (fiscally) efficient, "cut out fat", etc.
Even the loss of institutional knowledge can degrade the safety of a system over time.
Ever had to start maintaining a codebase after the greybeard who made it retired? Did you have any documentation to go off of? Anyone remaining in the company regard it as anything other than a production critical black box?
Now imagine that codebase is an industrial process, with 20 years of growth, add-ons, changes. Probably some mismatching control systems, and god only knows if the as-builts or red line plans for the additions are all correct or rectified with each other..
However, I don't trust systems to remain as robust as initially designed, after decades of undergoing constant pressure to reduce costs, make things more (fiscally) efficient, "cut out fat", etc.