As I noted in my original reply: the approach that makes the most sens to me (if 'disabling' Action Items that were previously deemed effective is a concern) is to require other systems to consult the CA/PA database for similar incidents. While I've certainly witnessed people trying to remove implemented action items, it has been far more common that the implemented Action Items didn't actually address root cause. An example of the latter would be "retraining users" to perform an overly-complicated process instead of simplifying/streamlining/poke-yoke the process.
I'm not a fan of looking backwards just for the purpose of looking backwards, especially for problems that were already solved (and found to be effectively solved).
