The question started as an opinion poll, but received a couple of answers anyway. It was then edited to a "pros and cons" question (and has received a couple of more answers since, but that's not relevant here).
The edit invalidated the earlier answers. I totally agree that if an answer was posted to an off-topic question, there shouldn't be much ground to complain if the improved question invalidated those answers.
However, one answer was useful without participating in the opinion poll, but now seems to not answer the current version of the question. I find this somewhat unfair because it pointed the OP in the right direction by showing a flaw in their approach. ("You shouldn't ask the internet for opinion, ask your employees what they want.")
What options do we have to preserve the useful answer while also making it a valid answer to the new question?
We could certainly ask dan1111 to update his answer in this case.
In the general case though, when a question has to be bent into shape, what should be our approach to preserve any existing useful answers?