He spoke of it in an interview, and I can't remember exactly which one atm. The blurb from his book Democracy at Work echoes this belief (the subtitle is literally "A Cure for Capitalism")

Capitalism as a system has spawned deepening economic crisis alongside its bought-and-paid-for political establishment. Neither serves the needs of our society. Whether it is secure, well-paid, and meaningful jobs or a sustainable relationship with the natural environment that we depend on, our society is not delivering the results people need and deserve.

One key cause for this intolerable state of affairs is the lack of genuine democracy in our economy as well as in our politics. The solution requires the institution of genuine economic democracy, starting with workers directing their own workplaces, as the basis for a genuine political democracy.