From Marcus Noland and Howard Pack, The Arab Economies in a Changing World, (Washington DC: Peterson Institute, 2007):
Across the region there is a tendency to rely on centralized regulatory intervention to facilitate the creation of economic rents and their channeling to politically preferred groups. By implication, cross-border economic integration, whether globally or regionally, is discouraged: Opening up would imply a loss of control and the concomitant ability to rig the local market to the benefit of regime supporters. All of this militates against a vibrant private sector that could promote increased productivity, employment, and growth. This combination of political illegitimacy and policy intervention makes it difficult for these economies to liberalize: Reform and the erosion of rents could undermine the very basis for political loyalty.
(via Leo Americanus)