Somebody: It has everything to do with socialism. Somehow, every Soviet-style socialist elite attempts to make like Ceausescu and plunder their own state. In fact, it's so universal we might as well consider it the natural evolution of any socialist revolution.
See, I agree to an extent with you and Wojtek that socialist experiments should be looked at individually, with an eye to the state of development on the eve of their revolutions. But, frankly, why are socialist countries so marked at birth to begin with? South Korea in the 1950's was a feudal, militarist, agrarian country with no industry to speak of, and living standards on a par with countries in Sub-Saharan Africa. It's moved on since then, become an industrialized nation, and has instituted a universal health care system, freedom of speech and democracy. Meanwhile, North Korea is still a garrison state, living in fear, with it's military first and Juche self reliance policies ever since the Korean War unofficially ended. Saying that capitalist enforced isolation and military threats explain it all is insufficient, because the DPRK is only the most extreme instance of what you see in the other socialist countries in history as well - a brittleness
and rigidity that only worsened over time.
Even when countries changed under socialism, like in Hungary under János Kádár's Goulash Communism, or less positively with Ceausescu overtures to the West, they never seemed to escape from their impoverished origins, they never made the leap to an industrialized democratic polity. They never, for example, developed agricultural productivity beyond the point where still 20% of the population were peasants. I don't know how socialism as practiced could have been an alternate model of development when it seemed to be most an alternate *phase* of development on the road to capitalist modernity.