I mean I remember being in elementary school art class and we were doing something and the teacher told us we were going to make a cornucopia for Thanksgiving.... And many blank stares... Followed by a "you know, the thing on the fruit of the loom..."

The so-called Mandela Effect has been discussed since at least the mid-late 90s. I can remember listening to Art Bell on late night radio when I was in probably middle school talking about it. Back then I don't remember FotL being one of the ones discussed.

If I understand the theory correctly, only those of a certain age and who had pre-knowledge of something, prior to the alleged timeline shift, would remember the "correct" version.

I don't remember if it's a part of the original 90s Mandela theory or an outgrowth, but they seem to think some event happened that changed the timeline, and we are now in a different, separate timeline from the one where FotL used a cornucopia (or Mandela dying in prison, as the name-origin). So, unless you were both alive prior to whatever this event was AND had knowledge of the FotL label, or Mandela's widely reported death, you'd be none the wiser to the change. One I've heard discussed was CERN - but that didn't happen until 2008 - easily a decade AFTER people were talking about the Mandela Effect.

But, as I remember the original conspiracy theory, it was purely a psyop - something that's not really possible if we're talking something like the FotL label.