Complete income inequality isn't even orthodox Marx - "From each according to his ability, to each according to his need" goes the standard quote by Marx; but that was his study of a specific utopia. (The rest of the cited work in fact goes on to rip its jaws into a transitional programme wrought out of "effective politicking" - pointed stuff.) The official CPSU line was then "To each according to his contribution" in the "transitional" period - through Trotsky and Lenin; so goes the degeneration.

I wonder how long it then took to get to imposed equality.