In the Middle East, dictatorships made sure that no one can emerge as a competitor to the incumbent tyrant, and that has gutted two generations worth of politicians. Either they become servile to the tyrant, or they are eliminated (physically, politically, socially, or otherwise ...)
Also, remember that this is a transitional government still. He has not been elected by a public ballot. That will take around 8 months to happen.
Outside of the USA, there are lots of engineers, doctors, university professors, ...etc. who make it to be top political post.
It will take time to built a political cadre again in these countries, and many will be professionals, not only managers or lawyers.