Even as a proud native of the 'Burgh (Eighty-Four, "Little" Washington, and New Wilmington) I never grew up with the "meal-between-bread bit".
Then, the Strip wasn't exactly "touristy". My first Primanti experience was back in the '80's when we visited my eldest while he was attending Carnegie-Mellon. I asked for my fries and slaw on the side and my son was horrified: "But you grew up here!" "Yeah, but I never drove a truck or walked in the Strip - especially at night".