Chickens and eggs. As it happens, though, we've got a perfect crossover experiment to monitor in the shape of the post-USSR Russia. Which is, if anything, ever more corrupt than the USSR. I cry foul on your citing the economic calculation problem; there seems to be a real problem with corruption in Russian society going back to before the command economy came in -- probably back to the social disruption of the civil war, if not earlier (to the Tsarist tax farmers).