Don't people still use manilla folders and hanging folders to keep records of various medical/insurance/tax/legal papers at home? (these industries haven't exactly digitized their workflow)

(I certainly do)

I do. My sister, however (not in tech), has a cardboard box with papers in it - and she is considered The Organized One by all her friends.

This sounds familiar. Most of my friends (both in an out of tech) have similar. We also often have a second box full of folders that we're One Day™ going to use to organise our important pieces of paper into.

a folder's a folder. Go into an office depot and you can buy boxes of them. people still use them all the time.