Actually, in Final Fantasy's case, it was capacity of N64 cartridges and their cost that sent Square away.
Final Fantasy VII once it was no longer happening on the N64, was I believe initially shifted over too the Sega Saturn before Sony came in and offered to publish, distribute the game world wide for them if they changed it to a PS1 title (unproven format at the time).
So yeah, Sony moneyhatted them to get the game, but it wasn't coming to Nintendo regardless due to their storage medium choice.