Capitalism works reasonably well as an economic system - provided that human beings are required to do effectively all of the labor. It worked far better than previous systems (slavery most notably).
But capitalism has a long list of grievances, not the least of which is that human labor has slowly become devalued over time. 50 years ago in Detroit, an unskilled laborer could make a living wage on the assembly line. The reason for that was simple: the assembly line, and the company that made its profits off of it, needed those workers. There was a need, and the car companies were more than willing to pay workers to fill those needs. The workers won, the company won, it was a positive sum game.
But that game is changing, thanks to robots.