Mathalamus
Emperor of Mathalia
By 1261 they made their 'miraculous' recovery, not least because the Fourth Crusade didn't actually damage the Byzantine state that much. Which they also seem to have managed in kangaru's ATL. The Byzantine state was militarily and economically the strongest of all its neighbors (save, economically, for the Venetians and possibly the Genoese). It successfully faced down multiple attacks from one of the most powerful centralized military machines in Europe. I truly do not see where you are coming from.
... well i got no good counter arguments. clearly i still need to do some more research. and read carefully.