How could a criminal forget a crime?
How can I arrange a murder without tipping off the murder that they are the criminal?
I agree that this question isn't yet the strongest it could be. In addition to your concerns--that it's very broad and has no definitive answer--another problem with questions like this is that they're not useful to future visitors.
Asking "what should I do to achieve X" is, IMHO (1) very close to asking "what should I write" -- off topic here -- and (2) really better suited for a discussion forum or a chat room. Ahem.
However, this is a concern to many writers, at one time or another.
(Now that this is being discussed here, I'm temporarily placing the question on hold so it's not a moving target if we have to do some significant editing.)
Why didn't the mods place this on hold?
There was a time on Writers.SE when the mods proactively closed borderline questions; however, over time, we learned that the community is good at providing excellent answers to borderline questions.
However, this clearly hasn't worked here. Out of the answers, the only ones that are really good are what's answer and lea's answer, both of which suggest avenues for future research. This is potentially useful to future users who may have written themselves into a corner.
The rest of the answers are specific suggestions. While many of them are good and some of them are fascinating, none are useful to future visitors.
What can be done to fix this?
Here's what I can think of for now:
You can either rewrite the question or leave it closed and open a new one. If you agree that the two answers I linked to above are good ones, maybe you could rewrite the question to fit those. They answered the implied question of "where can I look for inspiration to fix this problem." This is very likely to help future visitors, and also likely to be a question that's definitively answerable.
(If you don't like that option, you could also just leave the original question closed and write a new one. Or wait and see what other suggestions people think of.)