Has the theory worked any where other than Ireland? I've only spent a couple of weeks in Ireland so I'm no expert, but I get the impression that Ireland's rise has more to do with the entrepreneurship and diligence of its people than the EU. Though of course the opening of free trade and capital flows with the rest of Europe was probably critical. Still, that opening could have been accomplished wihtout 90% of the crap that being in the EU involves.
The Baltic States are growing like gangbusters. Poland is doing better than ok.
I visit Ireland frequently, but one cannot ignore the fact that pre-EU funding, the economy was stagnant and entrpreneurial enterprise was uncommon. It is however a strongly socialist country which of course has always held back it's economy. Many other economies are finding their feet in Europe with EU money, mainly the previously eastern economies.