The assumption that all communist states will automatically fail is a rather Marxesque one - historical inevitability, triumph of the chosen true system (in this case, liberal democracy) over the others, etc. Regardless of whether one wants to argue if the USSR or PRC or whoever is/was 'really' communist, I think we can probably agree that neither really pursued full communism, ie. the withering away of the state. So in the Soviet context, communism was just a fancy new gloss on a statist, authoritarian society where the government controls everything and dictates who gets what. It's not an innovation, and similar regimes under different names have lasted a long time, and indeed, the collapse of the USSR took most people, even 'Kremlin-watchers,' quite by surprise. With the additional resources posited by the OP and better management, the USSR could easily still be around today. And then, of course, there's the China route, but I don't know if that would be considered communism.