Although it is very difficult to prove it on purely scientific grounds, not least because economic issues can hardly be separated off political issues, I believe that the most appropriate answer is "to a great extent".

• The importance of political agency is an important matter toward regional integration. But it worth reminding that cultural and political similarities between state systems in Europe in case of broader cooperation on regional issues facilitated and aided the process of deeper integration between them.
• Comparing with the Middle East, despite the shared language and culture (between Arab countries in minimum), there are differences especially at political system and political culture. These differences exist between states and their divergence increased the weakness of their political institutions.

Yes, I believe that "political" at large includes more interdependent issues that are often taken for granted and not explicitly assessed. Cultural issues (still a wide cointainer of different concepts) may be nurtured and develop in a more or less similar/different way in various circumstances. They seem to preceed the political issues. At the end it all might boil down to what priorities a society sets, how they are ranked and who decides the composition of the society. At present, we might think of a kind of European society in construction with somewhat similar priorities at least in principle. Remember it has taken decades to get here and always with steps both forward and backwards. 

•  This question could lead us to broader challenge about regionalism and the factor of political agency in regional complexes in the third world. Are there any kind of political agency exist for facilitate regional integration? Comparative study of these regional schemes shed a light to that issue. 
• • The point is that it varies from one region to another. Even all developing countries regional projects are not the same. But something which is similar in majority of those cases is the complex of political institutions and weak political culture which weaken process of regionalism. It means that both states and their nations even social norms are different from each other. 
• • It is also important to forget the step by step process of broader regional integration. Especially the case of Middle East which depict existing challenges for regionalism proves this disability for analysis. Modeling a European type as a desired one at the time which even states of Middle East are in danger of collapse derails us from political realities in world politics