The "beacon of hope" scenario already played out in the Third Astral Era: the Allagans built their Crystal Tower, the common people rested on their laurels and stopped being able to work for themselves, and in the end they had consolidated power to such a huge extent that one targeted earthquake in Mor Dhona was enough to take out an entire empire. What really destroyed Allag? Lack of a backup plan.

(Kinda makes you wonder if restoring it is really such a good idea, but I've been thinking that the entire time.)