The southern Balcans BG is one of the three of four most strategic locations on earth;it connects three continents and and its sea routes dominate access to Africa Europe and Asia from the ancient times(see importance of Constantinople);it has been the opinion of strategists for very long judging and from the events in the aerea;the fact that is so strategically important is also the reason of how many tribes that later formed nations tried to enter or raid the aerea since the great migrations of the fourth century;that was mainly the reason of the importance of the Danube as its natural barrier.If The line of Danube was well protected rural life in the Balcans would have been at its peak.The Roman emperors liked to have their country villas in the Balcans(example

iocletian etc) but they never fortified enough the Danube to protect the region.
The Middle East contains extensive forms of desert in many places and Egypt has good production in the Nile Delta but extensive desert west and east of the Delta as well as in the south and deserts are unproductive; palestine is a poor soil area and libanon is limited;Messopotamia is better favoured,but that was only partially and at times under Roman rule.Romans were not sea people but the sea can be more productive than the land because apart from food it boosts commerce which was by far safer than travelling by land;Eastern Mediterranean was richer than Europe not because it had greater agricultural production,but because it had very advanced commerce and Industry whose products were safely transported by ships.You pay a lot of attention to agricultural production and you don't pay attention to the fact that Rome's decline and fall was essentially the fact that it remained an agrarian society unable to promote
other forms of development since it would be contrary to the interests of the latifundia owners,so was also medieval Europe and was backward for hundreds of years.