I don’t think “propsals that have attracted users” should be included in that. Most proposals have had minor “house keeping” edits done to them at some point by either one or multiple users. So it essentially disqualify 99% of the potential propsals right off.
The amount, quality, and usefulness of the information should be the criteria. Not that a few people over a ten year period changed “RFC” from upper to lower case, changed a comma to a period, or anything else along those lines.
Id also include “propsal pages with broad definitions of objects that aren’t osm specific and can be found somewhere else.” I’ve had a few deltion propsals reverted on pages that were something like boat=whatever, then a line half way down saying “A boat is a thing you put in the water to get across lakes in”, but nothing else. Then the person doing the revert said it was because that information was “relevent to the history of osm.” Which is ridiculous. So the content criteria for saving a page shouldn’t be “any comtent.”
As far as the age thing goes, I only use it as a measure for mostly empty pages as one veriable to help judge if the page might be worth saving in case someone might come along and edit it at some point. Like, if the page is blank, only has one edit, but is only a year old, who knows if the person who created it will come back or not. Whereas, with a ten year old page with no edits (beyond supperifical ones) or content since its original creation probably has zero chance of original creator of it ever wanting to come back and revise it. Plus, a close to zero chance of anyone else wanting to try and revive it. That’s the only situation where age plays a part for me and I never said otherwise. Obviously it would be stupid to delete all propsal pages after they have been around for a few years and I wouldn’t suggest it. Although for some reason I was treated as if that’s what I was doing.