1. Doesn't Eastern Anatolia have mines of some sort as well? Is there anything else other than sheep raising?
2. Of course they can't assimilate that many Turks by the end of Alexius's life, but eventually they may be able to.
1: I think so, but you're not going to get people moving to eastern Anatolia to become miners. Not in numbers, at least.
I'm referring to sheep raising as opposed to farmland, what else the economy had I'm not really any better informed than you.
2: Yep. It helps that TTL there isn't a second flood after the Mongols, so the Turks are drawn westward into Byzantium's orbit instead of influenced by Sufis and fresh Turcomen to cement the tilt towards Islam and a nonByzantine identity (I doubt Anatolia is truly "Hellenic" given how many diverse peoples have moved or been moved there, but it's comfortably "we speak Greek, hail the Theotokos, and write old fashioned poetry." kind of Rhomanian, which is enough - that's pretty much the basis the Empire is actually built on rather than anything "pure" culturally or racially).
So the main dilemma, and this is something any writer has to face, is how this sticks.
It's definitely solvable - as several timelines have shown (Age of Miracles and this one
https://www.alternatehistory.com/discussion/showthread.php?t=169430 being two I recommend) - but it's the part that will make or break whether or not Anatolia can be "regained".
Byzantium cannot afford to have things fall to pieces like they did in 1195-1203 OTL, IMO.