One of the main reasons communism fails is because it is so often forced on the community by a strong armed dictator. If they chose to switch to Communism, and the support of the people went with it, then I think it could work.
Also, communism would seem to be more fair and equal to those involved, than capitalism is. As a world which values equality, this would seem more ideal.
Of course, communism has its downsides too, such as the tendency and ease at which the government can abuse their power. I'm not advocating any particular form of government, but I just believe you are slightly mistaken :-)