Why is Marxism still a thing?
In short: bad ideas don't completely die just because they're bad. Bad ideas will always have their passionate fans, despite the popularity of the idea, or lack thereof.
I mean, Nazism is still a thing too, as is the fascism that often accompanies both Nazism and Marxism. The fact that these ideas persist means little, as nearly all ideas persist to some extent.
I'm curious whether you have read any of Orwell's essays on Socialism and Marxism? He was critical of Marxists mainly in that he felt they were too academic and out of touch, but he agreed with their fundamental goals. He fought alongside Marxists in the Spanish Civil War. A place to start would be The Road to Wiggen Pier.
I was trying to reply to the original comment not yours.