Hey, let's be clear about the relative success of Communism here.
You can't make the unsubstantiated claim that "Communism doesn't work" - that simply has no grounding. The "best" model of Communism we have as a point of reference is that of the Soviet Union.
Now, Marxist theory - as illustrated in the Communist Manifesto - suggests that over a slow period of time there will be an evolution of economic/political systems. This will originate from a feudalistic system, then over time will become more capitalistic – this is the stage we are at now. Eventually, capitalism is predicted to break down, and from that shattered foundation, a system of Communism can be established.
None of the Communist systems that have existed over the last hundred years have fitted with this model. Marx and Engels suggest that the move to Communism will be more of a gradual - perhaps evolutionary - change.
Back to our case in point, the Soviet Union. The Bolsheviks seized power in October 1917 (or November, depending on your preference of calendar) and imposed a system of “Communism” on Russia. Indeed, Lenin had to introduce the capitalistic NEP on the country just to restore the economy, before any kind of socialist economic system could be introduced. Essentially, the "capitalist" stage of Marxist theory was rushed through in under 10 years, and none of the slow progression was ever seen. The country, to all intents and purposes, went straight from a Feudal system to a Communist system. And then, if you look at Lenin, he was pretty out of touch with Marx, and Stalin had practically nothing in common with either Marx or Lenin - he is more readily compared to Peter the Great, than his predecessor.
Now, that is just one country, and I am using this as an example to make one simple point: there has never been a true system of Communism ever. If it ever does happen, there won't be some "uprising" or "mass revolution", it will be a gradual change, and move away from capitalism towards the ideals of Communism. Also, let us not forget that Marxist-Leninist theory (of which I am a great admirer) suggests that "world revolution" is required for Communism to succeed - unlike the ideal of "socialism in one country" that Stalin pushed for – and a worldwide system of Communism is required for it to actually get anywhere.
So, please don't just say "Communism doesn't work" when we haven't even seen a true Communist system, or given one a chance to work.