English Student makes a very good point in this answer:
Less than 5% of OP's even post an update, I think. It would be nice to know how their problem turned out.
On the main stackoverflow, or the electronics one, the asker will usually try proposed solutions and experiment, then post feedback. For example, "This solution offered best performance" or "this was what my problem was all about", stuff like that. Often a dialogue takes place, until the solution is found. This is very valuable, as anyone who has the same problem and googles the same Q&A later on will find this information very useful. People who answer also learn new things from this process. Negative feedback helps, too: someone with the same problem will be interested in not losing time researching solutions which did not work. My point is: the asker will usually provide feedback on answers, based on actually trying them.
This Q&A is quite the opposite. It feels a bit like opening a book at a random page. Someone tells their story, introduces some characters, then asks for help. People post answers, which are then voted up/down based on everyone's experience and/or subjective opinions: "Yeah... I think that would work."
However, only the asker can tell how they handled their problem in the end, if it worked or not, what they wished they could have done better, etc. This would actually be the most valuable information for anyone coming later to view the question, but it simply isn't there... Using scientific vocabulary, each answer is a hypothesis, but only the asker can perform experimental validation and decide which one worked.
Therefore: How to encourage askers to leave feedback and tell the end of the story, so this Q&A becomes more useful to future visitors?
This would also provide closure to people who write answers, and more important, allow them to learn from the results of their advice and keep them motivated. I still wonder how Tycho's cat situation turned out... It is nice to wonder how to write such feedback, but this doesn't address the issue that almost no-one bothers to actually do it. And even if they did, the answerers wouldn't be notified.
I'd suggest adding a timed reminder email which would be sent say, 2 weeks after the question was asked. Maybe a reputation bonus for motivation? Notifying the ones who answered? Other ideas?
For a quick example, I grabbed a random question from stackoverflow about a rather common SQL error. This example is interesting for several reasons.
Some of the answers are wrong.
Someone proficient in SQL will have no trouble solving this and telling which answers are wrong. However for a beginner, this will not be the case. The error message is pretty cryptic if you see it for the first time, and the wrong answers will lead them off track. Some are wrong for rather tricky reasons.
The accepted answer provides two solutions, one is right and safe, and the other may be a trap depending if the asker told the whole story or not.
Thus the asker took a minute to write a comment on the accepted answer to say that it solved its problem, which makes the whole thing a lot more useful for people with the same profile encountering the same problem.
This can be transposed to IPS: often answers will contain tons of suggestions. Simply accepting doesn't record which one worked for the benefit of future readers...
TL/DR: This is valuable feedback. How to get more?