from what i heard, cold war era slovenia got somewhat close. they were technically in the east bloc, but moscow had enough problems with yugoslavia as-is to micromanage them, so they could implement some common sense policies such as letting a factory fail if it doesn't work and just doing something else instead, without the common capitalist failings of letting some rich guy own the whole thing or making the bankruptcy the workers' problem. i haven't looked into it too deeply, so i expect their system was still imperfect in ways i don't really know about, but afaik they were rather prosperous for a soviet-allied state.