I remember trying on shoes at the shoe store as a kid. Mom would be sitting beside me, and the sales clerk would put my foot in one of those crazy caliper devices, presumably to measure length and width, then go in the back and bring out a pair of shoes. The clerk would then use a shoe horn to get both shoes on my feet, so I could walk around in them and tell mom how comfortable/uncomfortable they were. Not that it mattered. She would always send the clerk out back for a pair one or two sizes bigger anyhow. It would take me longer to outgrow them that way she said, and wearing an extra pair of socks for awhile was cheaper than buying a new pair of shoes every six months. A practical woman she was, my mom.
Anyhow, I've seen old shoe horns at the antique store, but I haven't actually used one (or had one used on me) for going on 50 years.