So he got the boom and bust cycles and inequality right but missed the ability of capitalism to reform itself and the establishment of welfare states which boosted upward social mobility and improved lives. He didn't foresee Marxist regimes killing people on a horrendous scale either. After ideology had become an opium or tool of deception for too many of his followers. But the most interesting thing about Marx was the healthy dose of scepticism he kept about ideas including his own (read with a free subscription). He was relatively unknown during his life with between nine and eleven people attending his funeral.
The MMM started out as a Marxist-Leninist party. Would you believe this? While a recent breakaway faction with interesting initials wants to privatise water.