Much like not all "capitalists", nor not all that endorse "democracy", are alike (there's variations of each), there's not a single form of "communism", nor is there typically blind acceptance of all facets of "Marxism", much like there's really no blind acceptance of Adam Smith's capitalism because the latter also failed.
Very True. Marxism has it's fundamentals which define it, but otherwise it can evolve into almost anything. Like all ideologies it mutates and changes according to the conditions. The problem is how "communism" so far has demanded ideological conformity and submission to the state as a basis for social organization which cripples the ability of individual's both to be free and to accept diversity as a political strength and as necessary for creative social development. So it kind of 'leaps' into existence because things get so bad under 'capitalism' (like after World War I when the whole of Europe went up in flames) but then it goes 'totalitarian' and suffocates any chance to develop into a free society with a future. We nearly had the whole world, dam it!
Oh, and on the subject of China, you should look up "Apec Blue". Communism might well be the future, but only if we can produce air quality which isn't lethal. It's just another way we're building a better future by making the present uninhabitable.