I don't expect maintainers to drop everything and fix the bug. I would hope that they would at least send an acknowledgement that they have seen the bug and might work on it. A snarky "that is not a bug but a feature", "it has been fixed in the latest release", or "you are an idiot, do this instead" is better than silence.
If you post a module to CPAN, you have an obligation to maintain it. I suspect fixing bugs is more beneficial to the community than writing new, cool stuff. Even if it is really boring. The user has an obligation to report bugs if they encounter them so the maintainer is not in the dark. One big advantage of open source is that the user can provide a fix or at least a test case. The maintainer's responsiblity is to apply the patch if it is suitable. Not let it sit there gathering dust.
The best example is bug 27, a major limitation in URI which is only 5 years old. People have even provided patches.