Dropping an idea from a long ago team offsite. Might be not feasible and declined.
Technical documentation gets outdated.
If someone realizes, then https://www.mediawiki.org/wiki/Template:Update can be added.
However, often someone does not realize.
Or does not know about that template.
Or that template does not exist on some wikis: https://wikitech.wikimedia.org/wiki/Template:Update
I appreciated that theguardian.com tells me that "This article is more than 2 years old":
To some extent this might also be possible with https://www.mediawiki.org/wiki/Extension:FlaggedRevs . Or with a gadget checking the last edit date (which still won't help if it's a minor edit).