The odd thing is that the two Baktrian settlements are only Large Towns. I have something like 30 small, large and huge cities. As I have said, ten of the large and huge cities have all of the available buildings already built. Seems like building or having the most advanced buildings is not the criteria for the most advanced faction. Also, Baktria is quite poor. Saba is the richest faction in my current campaign I am talking about. The Sweboz have the strongest military after me. AS follows them. So it can't be money, military, or the combination of both.