Explanatory theory of prevalence of Keynesianism

Steve: "That's just ridiculous! If Keynesianism is as flawed as you say that it is, then why are most economists either Keynesians or post-Keynesians?"

Josh: "Well, to argue that a theory or proposition is correct, because most experts agree to a theory or proposition, seems to be a fallacious appeal to authority as well as an appeal to the majority, simultaneously. However, if you are looking for a possible explanatory theory on why such would be the case, I might submit, that Keynesianism, as an economic theory, has conclusions which are of the interest to both the politicians/agents-of-the-State, as well as the economists themselves. Keynesianism tells the politicians and agents of the State, that the economy would be spurred by gratuitous borrowing and spending, which benefits the politicians, as they can procure political power by spending money that need not be taxed in the present-time; and the economists are benefited because Keynesianism would require that a group of specialized economic experts, operate the delicate controls of the economy, thus benefiting a host of economists in State employ."