Someday in the future, when you move 40.01 2021 Receipts from the Filing Cabinet to The Attic, will it keep that entire folder name? I don’t know if that helps decide what (if any) numbers go in The Attic now, but I do think it makes sense to keep the Filing Cabinet and The Attic physically separate because their backup routines are different.
I could see The Attic having its own 40-49 Receipts folder but with only old things in it. The Attic will instantly not be neat and tidy if most of it is non-J.D and it suddenly gets a J.D-identified folder moved into it. But it may not be neat and tidy now so it doesn’t matter! 
I also agree that symlinks = madness. This is a case where I think dumber is better.