>>722923614
FF1 sold well enough in the US thanks to heavy promotion from NoA at the time, so Square decided (after aborting an attempt to translate FF2 on the NES) to just release FF4 themselves as FF2. They didn't get the same numbers as NoA did for FF1 and were confused.
It could be because it was on a new system for the territory, because it was one of the lesser-promoted titles of the first six months (Gamepro gave it 5s across the board and it still didn't get much advertisement outside of a print ad referencing a late-game superboss), or whatever else. But Square saw weaker sales and thought the West needed tutoring.