I think you are missing the point: a user putting in a lot of effort into a bug report is usually trying to help themselves get the bug fixed.

As a maintainer, you will obviously look at that bug with more appreciation: but if you estimate it will take you 3 months of active development to fix it that you will have to spread over a full year of your weekends (which you can't afford), what would you do?

And what would a reasonable user rather see? Yes, this is an issue, but very hard to fix, and I don't have the time, or just letting the bug linger?