Currently there are 60 feature requests older than 10 years with 3 or less comments. It’s probably worth going through them and see if some can be closed, especially if the proposed feature is not well thought out or if there was some initial pushback.
As you mentioned, if there is some discussion and/or patches, it might be better to leave it open.
FWIW I don’t entirely agree with this premise, as I explained here: Triaging/reviewing/fixing issues and PRs