I am a bit puzzled by the quote below, from here (emphasis mine):
Modern monetary theorists have helped clarify the obvious point that private banks are not essential to the design of the system. It would be possible for the Federal Reserve to bypass the banks which profit by selling bonds to the Fed and, instead, invest the proceeds, for instance, in a public “Infrastructure Bank” [...]
So, central banks pursue open market operations by selling/buying bonds from banks or other financial institutions involved in these operations. Maybe the author is referring to the "buying side" of these operations, whereby the central banks buy short-term debt from banks?
Does this mean that banks only sell these bonds if they expect a profit? Does that also mean that banks only buy these bonds at a profit? How does this profit materialise? Through a discount/premium over the price at which these bonds are bought/sold? Or is the author simply referring to the fact that these bonds have positive nominal interest rates? (but these bonds are usually from the government, so it is not the central bank who is paying the interest)
Does this mean that banks are in every single transaction profiting from such operations?
(sorry, a lot of questions but they are very much related).