Do you think it's because they are Capitalist, or do you think it's because they're developed, and started industrializing earlier, with plentiful access to global trade?
It absolutely matters. If you're tying development to quality of life, which I agree with, you also have to make the absolute claim that Socialist states can't develop, which I disagree with. Capitalism is only a few hundred years old anyways, and already is failing, ie disparity is continuing to accelerate to unsustainable levels.
First of all, what is a "Communist state?" There's no such thing, so if you clarify what you are referring to, that would help.
Secondly, clarify what you mean by "failed," because either you don't know much about leftist states or you're using a different meaning of the word "failed."
Finally, what do you mean "the idea sounds good on paper?" If it sounds good on paper, ie it works in theory, what about reality is an unknown factor? If humans can't grasp it (whatever that means), then it doesn't work in theory!
Communism is a Stateless, Classless, Moneyless society. It cannot be adopted by a state. You're referring to Socialist states.
You clearly do have problems with Socialism, or at least some forms. Democratic Socialism is Worker Ownership of the Means of Production, organized similar to a liberal democracy. That's fine, but the goal of Democratic Socialism is still Communism, eventually.
You were not in fact referring to Communism, which is why I asked that question in the first place.
The USSR was a Union of Soviet Socialist Republics. It was headed by a Communist Party, ie a party trying to build towards Communism, but through Socialism. The end-goal of Socialism is to eventually do away with the state, class, and money, as all 3 are used to oppress people, creating Communism. Same with Cuba.
Sweden is not Socialist, it's a Social Democracy. The mode of production is Capitalism, with expanded social safety nets. Some industries are nationalized, but Capital is largely in the hands of Capitalists, not shared among Workers. Actual Democratic Socialism would be like if Sweden's Unions took ownership of all Industry, but maintained government structures.
I hope that clears things up! What you call Communism, is in fact a specific form of Marxist-Leninist Socialism, most likely.
What do you mean by successful? By most metrics, implementations have led to higher life expectancies, literacy rates, and more, when compared to preceding systems. In forms like Worker co-operatives, these systems are more stable than Capitalist businesses with higher satisfaction, and in cases like the EZLN where its more Libertarian Socialist, they have successfully created a community for themselves.
That's why I tried to ask why you think Socialist states can't develop, because quality of life follows development, not Capitalism.
Well, like I said, that's the perception I've had from observing nations such as Cuba, Russia and, more recently, Venezuela.
I'll concede that some programs under socialism/communism benefit a lot of people. But at what cost? Failing infrastructure, brain drain, indoctrination...
What country under communism has experienced such improvement in quality of life?