Marxists claim to be scientific in their thinking and yet treat Marx as some infallible prophet. The idea that all of history is "class struggle" is obvious bunkum, especially considering that for tens of thousands of years of our history we barely had anything resembling a class structure. Even within recorded history there are multiple other factors. The emergence of AI and transhumanism also mounts a challenge to Marxist orthodoxy, as you cannot have a true proletariat when jobs are automated and people are being turned into cyborgs.