There were three important factors:
3) Khazars!
3. The Khazars - do they and the Byzantines really have a "special relationship?" There are big gaps where there is little contact.
To further prove my point about the extent of eastern expansion in the period roughly corresponding to the time of the Macedonian Dynasty, here's a quick map showing the approximate frontiers in 850 (black line) and 1050 (red line). At the very least, in the south east I can see expansion of about 225 miles, while from Cappadocia to Armenia it's more like 400 miles! The scale is at the bottom left of the screen.
It's unrelated from the OP, but I stand by the statement that Timur excepted, the Ottomans never really faced an enemy that was their equal until the 18th century. Hungary and the Hapsburgs were both very distracted by European politics and lacked the superb centralised organisation of the Ottoman state, and Safavid Persia lacked the resources available to the Ottomans. So I stand by the fact that the Ottomans (and the classical Romans too) in their golden age did not face any really dangerous opposition to their hegemony, in contrast to the medieval Romans and the later Ottomans, both of whom managed to cling on for far longer than they should have done due to a mixture of luck and ingenuity. This, you should note, is not overrating the Ottomans- I believe that their empire was a unique and dynamic one that really did better than it should have done, due to the genius of their administration and rule.
You make a good case but looking over the wiki article it is clear that the narrative is VERY confused. Wiki also depends on Kaegi, who is generally too trusting of the sources.
Also there are vast swathes of Asia Minor that are not even mentioned, particularly the south-west. The Persian Wars cannot account for urban decline here.
I agree with your central point - Asia Minor/Anatolia undoubtedly was poor until into the 10th C was poor but also the core of the empire. I think you need to rate the advance as an 867-1054 phenomenon rather than a 400 year event. It's still not fast of course.
I disagree with the details of your case though.
1. The Arabs held the passes until the 10th C. The Byzantines were therefore on the back foot.
2. This seems out of date, and seems to suggest the mass peasant mobilisation described by Ostrogorsky. This definitely was not the case. The purpose of the themes was to produce gentry heavy cavalry. The Byzantine advantage was due to internal unity/bureaucratic organisation.
3. The Khazars - do they and the Byzantines really have a "special relationship?" There are big gaps where there is little contact.
I wrote my M.Phil thesis on the Khazars and Byzantium c630-965 C.E. at Oxford University in 2000.
In it, I argued that the "special relationship" of the Khazars with the Byzantines was largely a myth constructed by later historians - there was as much conflict as there was cooperation between these two powers. You can make an equally strong case that the real "special relationship" was between the Khazars and the Caliphate (or its local successor Emirs in the Darband and Shirvan region).
So, I am afraid I don't think that the Khazar point can stand.
I'm also inclined to think that plague was exaggerated, no-one has ever discovered a 6th century plague pit.
How long does it take after a re-conquest for the land to be productive again? I'm thinking of the Komnenos regaining western Anatolia during the Crusdades.
Apparently the Seljuks devastated a wide swathe of territory on their side of the frontier so that an army crossing it would have to carry and use its own supplies, and by the time it crossed would be weakened and ripe for harrassment. IIUC this was a major problem for the 1st and 1101 Crusades. But by 1149, 50 years later the 2nd Crusade used what would have to had been this very swathe of territory as a source of supply, indicating that it had largely recovered from its use as a dead zone for crossing armies within a couple of decades of re-conquest.
Eh....
There are other possible explanations for that. And it's pretty clearly yersina pestis that was mucking about in Europe.
Ingrid Wiechmann and Gisela Grupe, ‘Detection of Yersinia pestis DNA in two early medieval skeletal finds from Aschheim (Upper Bavaria, 6th century A.D.)’, Am. J. Physical Anthropol., 2005, 126: 48–55.
And of course, we didn't find a plague pit in Athens until 1996.
Constance Holden, "Athenian Plague Probe," Science 274 (22 Nov 1996) 1307.
Is there a good source for following the reconquest of western Anatolia by the Komnenos? Was the region taken in chunks or in one fell swoop? Where was the 1147 border, and how long had that line been established? (maps tend to be very vague)
I'd think that 10 years after reconquest fruit trees, vines, houses, fords etc would be well established again, depending on what is meant by the term 'devastated'. For example it might be possible to rebuild burnt-out and damaged stone buildings rather than start totally afresh.
John took the region by bits, it was Manuel that tried to do it in large gulps IIRC.
The fact that the Nicaean state established in the aftermath of 1204 was fully viable is evidence that by that time the area had recovered and become self-sustaining.
Byzantine Anatolia was recovering, but it took time and - above all - security, which was cut short by political instability and a lack of attention from the Emperors after Manuel I.