Perhaps it would be more fruitful to discuss if you have a concrete example in mind. I haven't personally seen or closed new questions as dupes if answers on the existing questions have been noted as being not up-to-date.

The goal of editing an existing answer is definitely not to change the original answerer's intent.

The tools to solve the problems you identified are available. As you've alluded to, it's up to each user whether they choose to make use of them.