There is no easy fix to this. This is a player-made problem. You don't need high amounts of gil to play the game. You only need gil for when you're lazy (you raid, but you don't craft, so you buy food or pots; housing is completely optional; crafted battlegear is not necessary, etc). If people got rich once, they will be again and we're back to the same issue. Just leave it as is; having max gil means nothing, so don't make it mean something by gating it behind frivolous things poorer people might want. It doesn't solve the issue.