I don't know how much more clearly the authors could have put it. Those three areas show less influence from anyone. It's isolation and then drift.
As for the "there must be Turkish" blood in Greece, Albania and other countries", bigsnake I'm sure knows better than I do, so if I go wrong, he may, of course, correct me, but this is my understanding:
By the time of the Ottoman take over, they were Muslim, and the inhabitants were Christian of one variety or another.
It boggles the imagination that an Ottoman family would allow their daughters to abjure their faith, turn apostate, and go marry a Christian Greek and live in that community. If a Christian Greek male wished to marry a Muslim girl, he would need to convert, be circumcised, and become part of the Ottoman community, and when they left he and his progeny would be part of the group going into exile.
Now, I think a Christian girl could become a wife or concubine to a Turk, and could then even keep her Christian faith, but her children would then become part of the Ottoman society.
From what I've read there was no such thing as "civil marriage"; marriages were performed by a holy man or teacher of that particular faith. A Christian and a Muslim couldn't marry without one of them converting or at least the ceremony being performed by either a Christian priest or a Muslim officiate.
So, if anything, I think there is Balkan ancestry in Ottoman Turks, but I don't see how it could have happened the other way around, except perhaps where whole groups converted to Islam, as many Albanians did. I don't know if in that case intermarriage did occur between Albanian Muslims and Muslims from Turkey, and if it did whether they went into exile back to Turkey or not.