Sharlayan & Poroggo

[Morningstar1337]

I really wonder why they didn't bother to take care of the entire city-state after the exodus. It might've been funny to see the Poroggos living there.

Because the "Sharlayan" we can access is not actually Sharlayan, but a colony they started when they went to Eorzea. The actual City-state is outside Eorzea in "The Old World"

Of course Given the AST Quest's antagonist's opinion on Eorzea (and how they are in control of the Forum) I suspect that once Garlemald mad its plans known, most of the Colony immediately declared Eorzea inherently worthless because anything of value would had been razed or stolen by the Empire (or the Calamity, but its unlikely that they didn't know of that until it happened) and abandoned everything, probably hoping that the Garleans would destroy their experiments...

At least they didn't offer the colony and their resources to Garlemald, the Empire is troublesome enough with just Ala Mhigo as their only sphere of influence within Eorzea (and before you ask, Selling land to other countries is a thing)