The average GDP per capita (PPP US$) in high-income OECD countries is $30,181, according to the United Nations Development Program (cf. <http://hdr.undp.org/statistics/data/country_fact_sheets/cty_fs_ESP.html>).
Give each and every citizen and resident in the Middle East $30,181 per year,
[WS:] Actually, it is not that far from it http://hdr.undp.org/statistics/data/indicators.cfm?x=5&y=2&z=1
For example, United Arab Emirates with per capita GDP $22,420 are ahead of Spain ($22,391), Israel ($20,033), Greece ($19,954), or Portugal($18,126) - yet do not strike me as a paragon of liberal thought. The feudal and autocratic Saudi Arabia ($13,226) is well above most Eastern European countries, not to mention the world average of $8,299.
While we are at that, the not so liberal United States ($37,562) is well above the ultra liberal Netherlands ($29,371) or Denmark ($31,465) or Sweden ($26,750).
Something does not seem to compute in the relationship between political liberalism and GDP that you claim.
Wojtek