I would guess, actually, that in percentage terms the amount of migration was probably quite comparable. The majority of Greeks really did not want to go East, and there are plenty of examples of colonies set up by Alexander attempting to flee back to the Aegean during the early wars of the Successors.There certainly was a not entirely insignificant movement East - colonists invited and Greek/Macedonian cities deliberately planted and nurtured. Outremer never had as much luck there.
True- but the same can equally be said about the early Caliphate, or indeed the early Roman Empire.But I think the problem is more that the Crusader States rest on very shallow foundations, and the external opposition is fierce - so they rest pretty much on the strength of their armies with little inclination by the locals to be that worked up in their defense beyond that.
Why?On Egypt:
Egypt in the fourth century BC more likely to find a different ruler merely a change of masters than in the twelfth or thirteenth.
Again, I don't disagree with you. But I have my doubts the Arab peasantry of both Christian and Muslim faith that inhabited Outremer in the eleventh century was especially dedicated to a Turkish government that was itself an alien incursor into a world that'd been Byzantine/Arabic for the past four hundred or so years.Not as familiar with the seventh century, but even if it's poppycock that the Monophysites welcomed/aided the Arab/Muslim invaders, they certainly weren't fiercely dedicated to Constantinople (as a consequence of the Last War and things from the state's attempt to recover from that, from what I can tell).
Don't disagree here either- but once again, you can make the same point about lots of other conquests that did IOTL stick.And being dependent on being bailed out by foreign intervention is a decidedly weak reed to lean on. European monarchs - and the Papacy - have plenty of concerns of their own, the Holy Land is at most one of them.
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I'm certainly not saying that the survival of the Crusader States is particularly likely, or that there are not serious and formidable objects in the way of their survival. But I do think that you have a tendency to airily dismiss a lot of things as being "ASB" based purely on what you see as internal factors involved- our discussions on the survivability of the WRE is another example of this. I think calling surviving Crusader States "ASB" is quite a serious abuse of the term.