Similarly, I often report problems on Google Maps since they actually send email updates about your report and tell you when it's fixed, whereas I never do with Apple Maps since they don't provide any feedback.
Having your bug get fixed is perhaps the most meaningful update possible, and that's the one you'll never get if you don't file bugs.
I get your pain, I really do. I've filed many hundreds of bug reports with Apple. And many of those never got updates, or (more often) got a single update telling me it's a duplicate. It sucks to spend a bunch of time compiling a bug report only to be told that it's a duplicate.
But many of the bugs actually got real feedback, and many of them got fixed. Sure, if I hadn't filed those bugs, maybe someone else would, so some of those would have gotten fixed anyway, but maybe not as fast, and a bunch of them probably wouldn't have been fixed at all simply because most people don't get around to filing bug reports.
However, internally they use that bug tracker for everything. If it isn't in there as a bug, it likely isn't on the "radar" to be fixed.
BTW, it is unfortunate they don't make public views of bugs available (a la openradar) but if you have an issue impacting you marked as a duplicate, it is not closed. You can both amend your issue with new information and you can request updates on the status of the primary bug.