While I don't neccessarily disagree that our "blunt" or interpretative guidelines on duplicates do occasionally close the wrong things, or close things against the wrong things, and often without complete consistency, I'm not sure I agree that we need a flow-chart spelling out exactly what to do.
While there are a number of reasons for closing duplicates in the way that we do, there is only one important effect: by closing something we answer it with the duplicate (both for this person and somebody coming in with the same symptoms as this person).
It doesn't matter if they post a load of garbage about their space laser configuration. If the actual problem was caused by their graphics drivers, somebody else incorrectly thinking their space lasers are the problem is going to find the solution through the same vector now.
There's a ton of circumstance and edge-case history around this that makes spelling everything out a serious distraction to just getting things done.
Why was this one left open but mine closed?
Why was my older question closed?
My question was much better, please reverse the decision.
My question was about 16.04 but that answer says it's for 12.04!
Edit the original question/answer if you're sure they apply. If the new OP has tested them and they don't work, edit that into the question and move reopen. Inter-version duplicates are one of the harder things to marshal accurately.My answer is on the closed version which nobody votes for any more. That's not fair.
Etc, etc.
And that [ton of history] exists because there are moments where things aren't clean. Where we have a new question with 50 answers that are all identical to the one in a past example. We can close, but do we merge? Bigger picture, should people be rewarded for posting the same answers over and over again when they should be closing?
My point here is when things get gritty, a set list of rules isn't going to help that much. There's always another situation where somebody might actually be right and that the universe benefits from us breaking those rules. Thankfully we have Meta to argue about individual cases.
Your points about conflating causation with remedy are completely valid and people should certainly be very careful (and explicit; it costs nothing to leave a comment explaining you think their space lasers aren't the issue)... But ultimately, just do what does the best thing for the OP user and the next user with the OPs problems.
Try not to get too bogged down in making sure the questions are exactly the same. We can always re-open if required.
On the other side of this, as somebody having their question incorrectly closed for being duplicate, this can highlight simple ways to improve your question to make it more clear what you're asking.
If you're certain* your question is about space lasers and you've already read that post about wifi drivers, say that. Explain your reasoning if there's a slight technical difference. Your review jury only has what they can read to judge if it's a duplicate or not. The easier you can make this, the better.
Even if the process ends up with your question closed, then edited and then reopened, that's better than keeping an ambiguous question alive when it's getting answers for the wrong thing. That's a big waste of time.
* By that I mean you don't just say you've tried something out.