(Except that they obviously tried state socialism, which is supposed to be the precursor to socialism, which itself is a precursor to communism, but going through the precursor steps to communism doesn't count as trying communism because... reasons.)
In true communism, the leaders are no longer necessary; the people will starve themselves, in the most efficient manner possible.~
The idea Lenin expressed in "State and Revolution" was the idea of the wilting of the state into nothing as it becomes useless without class antagonisms to subdue.
If you follow Marx, the only universal, the step that both China and the USSR skipped which might be why they ended up the way they did, was that Socialism is supposed to evolve from advanced capitalism which produces the abundance of tools and facilities that make a new more equitable highly developed civilization possible.
The interesting lede here is that the USA is, unlike a poor peasant country, in a state of advanced capitalism and is the most wealthy country in world history. It is also the imperial power that oppresses the rest of the world rather than vice versa. These unique circumstances raise the possibility that Marx's vision might be best fulfilled here, not over there.
You're not getting a worker's paradise here unless you shove some people up against the wall.