It's true, they tried this already. Prices used to be higher, but people whined and whined about not enough ways to make gil, their repair bills after a dungeon, and how dark matter was a waste of time and space.

I'd like to see an Aetheryte blackout, where it's no longer possible to teleport anywhere, but that doesn't mean it'll happen OR that it's a good idea. Of course, it would save billions of gil overall on a server...........