Not my experience with Apple: I've had years-old bug reports where Apple suddenly emailed me and asked me to confirm that the bug was fixed in the latest developer preview (for an major OS version later).

Same experience here, I have 2 year old bugs fixed 2 major version later.

Unfortunately the official bug report system is opaque though.

Unfortunately the other common case for Apple is that your bug just gets marked as a duplicate, and since you only have visibility to the bugs you opened, you lose all tracking.

Filing a bug for Apple is worth the effort even if they mark it as duplicate. Duplicate reports count as "votes", the more people file the same bug the higher priority it enjoys. Apple employees mention this regularly on the Apple Developer Forums and encourage everyone to file bugs.

To be fair, testing a hardware-specific bug is a bit more complex.

In case it wasn't clear from the parent, Debian doesn't do this (at least not automatically).