In order to live in capitalism, you need to have a sense of humor. Once you are living in capitalism, and enjoying yourself --- and once you are suitably relaxed --- you need to be serious: that too. You need seriousness too --- in order to improve, reform and stabilize your system. Therefore it is my position that capitalism has to be stabilized. Stabilization is not a crime.
That means that the left should not be offended --- by the suggestion that one needs to stabilize capitalism! (Instead of what? Revolution!?) The responsibility of capitalism is to give persons the chance to earn a living and to live.
(On the serious side) it is the responsibility of persons living in capitalism to change it. It is the responsibility of persons living in capitalism to reform it. It is their responsibility to make it better. But we are falling down on that job, or on our responsibility to reform, monitor and stabilize the system.
A version of capitalism that has only what we call the private sector is a bad version ---- a bad dream. You could call our current economic system a failing and declined, or, sort of sterilized, neutered, or doomed capitalism. It is no longer humorous! As it loses that particular quality as well as the essential character of diversity ---- it perverse: merely perverse. Capitalism needs to be diverse. It needs no perversity but rather the diversity of the public sector.
The public sector is different ---- than the private sector. (Which is why, I suppose, two labels exist!) The two are different, then, and what the public sector is, and how it is to operate vis-a-vis the economy as a whole, and how the relationship is to be sustained, needs to be worked out; and that's the "how" problem.
Our problem is the "how" of governance. It is the "how" of governance (regulation), not "whether." But it is a step forward to understand this, at least: the two concepts, of "capitalism" and "public sector," are not contradictions.
To sum all this up, capitalism needs a public sector. One quality of a public sector is governance. If a quality of capitalism is that it needs both a public sector and a private sector, then, since the public sector part needs to be governed, capitalism needs to be governed. Maybe the private sector part does not but....who decides what part is the private sector and what part the public sector?
It is not possible to say that that decision should be left to the private sector.