The solution is not destruction and a lot of manual work. It's software. Make it more usable. Keep a record of last page updates and last page visits. Flag page

The solution is not destruction and a lot of manual work. It's software. Make it more usable. Keep a record of last page updates and last page visits. Flag pages that according to your settings (default no views in a year, no updates in three years) for review for update or archival. Archive old pages compressed heavily but in he wiki data store. Mark them as potentially obsolete but possibly of historical interest. Leave links to them intact and have an option to restore the page to intake status for viewing.