Something exists in capitalism so therefore it can't be socialism? And im not going to get into another circular reasoning of "It didn't exist in that form before therefore it is impossible now." At no point have you pointed out anything Marx supported that is a problem other than a generalized brush of everything.
90% of Marxist work is a study of capitalism, much of which we still hold true today, so to me you look like everyone else that blindly dismisses what he said without learning what he even did or said.
I didn't say it wasn't socialism. I said it wasn't a counterexample. As for whether you still think it's worth taking Marx seriously as an economist, I'm guessing you'd laugh at someone citing Smith. Yet one had a better track record than the other. My point was simply that a theory should be judged on its merits, it's predictions, it's actual outcomes.