[scarmig]

Marx didn't predict that capitalism wouldn't generate wealth. On the contrary, he believed it was the most economically revolutionary structure the world had yet devised and would create untold wealth. That's entirely consistent with the world we see.

To be very specific, where he fell short was predicting a secular decline in the rate of profit. This wasn't a crazy error--most early economists also believed it--but it was very wrong, and his analysis of the failure of capitalism rests on that false premise.

[Der_Einzige]

He's referring to marx belief in the "tendency for the rate of profit to fall" which is literally objectively wrong and the opposite of it is accepted within economics.

This is the accepted explanation, which implies that the rate of profit rises over time

https://en.m.wikipedia.org/wiki/Okishio%27s_theorem

Btw, marx predicted that capitalism is inevitably destroyed due to tendency for the rate of profit to fall. I believe capitalism is the strongest that it's ever been right now.

[scarmig]

I'd emphasize not only that there have been advances in theory but also in, more importantly, the empirical evidence. Marxism is a scientific theory in the sense that it can be falsified, and if you look at the rate of profit over time in most countries and periods, the evidence very strongly falsifies Marxism. Even if someone refuted Okishio, Marxism makes predictions about capitalist economics that simply aren't consistent with the world we see.