Part of the appeal or Professor Richard Wolff's economics speech is his ability to look back in history and draw parallels for what exists today. All time periods are unique, and history doesn't repeat itself in the most literal sense, but there's much to learn from the events of the past, and Wolff helps to elucidate that.
In particular, he focuses on the current economy as compared to early in the 20th century. In the 20s through until the 40s, the world economy wasn't in very good shape thanks to the Great Depression. These economic issues arose as a result of too much capital power in the control of private enterprises, and John Maynard Keynes, a British economist, successfully demonstrated how capitalism could be adjusted to prevent widespread poverty and the like. Keynesian economics gained popularity and acceptance, but its hold has slowly diminished to the point where we might lose it today.