Actually, this has a LOT to do with the Mana games (called the Seiken Densetsu or "Legend of the Sacred Sword"). Originally Square was going to make an RPG called Seiken Densetsu, but it was too ambitious so they had to scrap that idea and created Final Fantasy, because they suspected it would be their last game.

Oddly, they did end up creating Seiken Densetsu (Final Fantasy Adventure in the States). But how much that game has to do with their original plans remains to be seen.