In game econs will be fine in a few months. No one is going to go absolutely broke in 5 seconds and stay broke if they know how to make money. If demand goes up on larger servers and increases prices, smaller servers have the advantage of undercutting and therefore bringing in more capital. If Demand is cheaper on larger servers, smaller servers will have to compete, forcing prices to drop and incentivising crafting as a back means to make money. This is going to happen on an item by item basis and result in gil being more evenly distributed regardless of your realm. There will be some richer servers, and some poorer ones, but that is fine.

Also, btw, this might help solve some of the housing crisis. If servers are being a lot less relevant, transfering your character to a server where housing is available is a lot more justified now. We're just about playing in a defacto 1 overworld server now.