I know I'm going to get downvoted for this, but since the USSR was a historical failure and Marxists claim China isn't actually Communist but Capitalist, can't we say the same for Marxism? An interesting historical curiosity, but it was never actually implemented and thus can't be said to have ever taken off.
Both Georgists and Marxists get to complain about how things would be so much better if someone would actually just do it the right way for once. I say this as a left leaning Georgist Libertarian, to my heart in the right place Marxist cousins.