Honestly, if the "duplicate" question is older than 5 or 10 years they should force the mod to prove its resolved the same way before marking it duplicate.
Generally, the people doing this are familiar with the material. Fast closures are motivated by an unconscious "ugh, not THIS question again". And the kinds of things that get asked over and over usually don't change very much.
There's a particular type of question asker who likes to say "what's the way to do this in [current year]?" as if to imply that it should be something different from before. But it very often isn't. And indeed, developers complain when languages/libraries/ecosystems change too quickly, which makes language designers/library authors more conservative about those changes.
The top answer is still up to date