I don’t think true Marxism can ever be tried because human beings (like most primates) have an innate sense of fairness and Communism is as close as we can get - in order for that to work you have to brainwash a country into an alternate reality and shoot everyone who disagrees with you a la the Kim family.
So I don’t think it’s a route we want to go down. However unfair communism might be, capitalism is also a loaded system. The issues with inheriting huge swathes of wealth, off-shore accounting, the hoarding of obscene amounts of money and the purchasing of gold plated status symbols is something which needs addressing.
I think we’re moving back towards a more Victorian model of philanthropy from our wealthiest citizens, but that’s not the same as taking a more socialist-democratic stance and ensuring that everyone pays into the system and takes out at the point of need.
True Marxism may come but only organically and only if society can move past the pursuit of money at all costs. Won’t happen in my lifetime but I remain hopeful for a few generations down the line.