What you are calling "ethical business practices" didn't come about because of some newly arisen need for them. They came about because of the newly arisen possibility of them. Until very recently in history, it was taken for granted by the entire human race that every moment of human existence was a struggle for survival for almost everybody on the planet. The possibility to live to see the next year required exposing oneself to constant danger in back breaking endless labor, and getting one's children to help do it. Capitalism didn't bring about those conditions that we in America today think we deserve to be free of just by existing. Capitalism made it possible for large numbers of people to escape them for the first time in history. Yes, Marxism arose in response to that, but not as a correction to some harm done by capitalism, but out of envy due to the fact that some people enjoyed more improvements than others.