We're not talking about the end of the ARR story. We're talking about the beginning of ARR.
The NPCs mention many, many adventurers at the Battle of Carteneau, many more than just the one team of 4-8 (from their in-game perspective) that successfully disabled the one lunar transmitter, the one team that maybe later went on to defeat the one Nael von Darnus. They even refer to these "countless adventurers" as the Warriors of Light, and that all of them just vanished. The NPCs certainly mean more than just 4-8 adventurers.
Maybe the NPCs are just "meta-gaming" about that, but now they have no reason to not remember the majority of adventurers in v1 who met and helped them through even just the original v1 main story. Remember how it works: In-game, each of our characters is the single person who drives the stories along. The NPCs don't ever say "we don't need you to defeat Nael because someone arrived earlier and already did it". So there's no reason they would forget each of our characters.
It would have made more sense for the devs to cover at least the v1 adventurers who played during the 7th umbral era story line with the teleport entrance to ARR as expected. Then those characters would be covered by the amnesia magic, and get the part of the story with NPCs not recognizing them and/or vaguely remembering them, until of course Minfilia said she knew. Those are all original main story NPCs, not 7th umbral era story NPCs. That would mark the "End of Special Treatment" in ARR for those characters. Everyone's happy. (Of course the characters who completed 7th umbral era quests would get more references to their previous accomplishments against the Garleans and Nael as the ARR main story unfolds.)
But instead most v1 characters were "left behind", and nothing is explained. Worse, paying customers who supported v1 during 2012 are left with a sense that their time was wasted, their characters' accomplishments discarded and forgotten by a world and its developers they spent countless hours helping and supporting.