The list allows only a few of the most recent to appear on the 'Quick Switch' list. The Libraries still exist.
Consider making a custom column: 'Read" (there are various threads discussion type and usage). Then you can use filters (saved searches) to only show #read :true or (Not) #read:false
Create the colums in all Libraries: Use the Bulk Metadata editor to Populate the Read column: THEN
Merge back into the main Library