Bug reports are not known defects, at any kind of scale half of them will be already fixed, misunderstandings, bad data in, or related to an unusual setup.
Closing the bug is a way of saying: sorry this doesn’t look too important and we don’t have time to look at this given the other more important things (bugs/features) we plan to work on.
If it’s closed as stale after 6-12 months (multiple humans will have seen it) OR triaged by a human and marked as won’t fix I think that’s reasonable.
> at any kind of scale half of them will be already fixed, misunderstandings, bad data in,
Here you're referring to a class of bug reports that's uninteresting for this discussion, because they're invalid (i.e. they don't represent an actual bug). We're talking about valid bugs that have not been fixed.
> or related to an unusual setup
Unusual, but ostensibly supported? Then there exists a bug.