Why is anyone still challenging capitalism?

Given the evidence of the superiority of capitalism in achieving prosperity, isn’t it astonishing we still debate its merits?

Filmmaker Michael Moore actually made an anti-capitalism “documentary” called “Capitalism: A Love Story.” Moore says: “Capitalism is an evil, and you cannot regulate evil. You have to eliminate it and replace it with something that is good for all people.” Is it relevant that Moore’s net worth is reported around $50 million, give or take a few mil, and that his accumulation of wealth occurred within the system of free markets that he trashes?