There's a difference between "works" and "has worked". And it hasn't existed for "a long period of time", just long when compared against the lifetime of moder

There's a difference between "works" and "has worked". And it hasn't existed for "a long period of time", just long when compared against the lifetime of modern economics. Which is not to say it's wrong. Merely that the world hasn't settled on Keynesianism as the One True Path™, and there exists no logical proof that it is successful, much less the only successful scheme, because you can't construct irrefutable proofs when you have to include human behavior. The bashing may be popular now, but Keynesianism has been popular for quite a while, during a period of great wealth increase (which you cannot attribute solely to it, for the same reasons you cannot prove it works), and I suspect it has blinded people to other possibilities. At least this gets people talking about it, and it has generally been civil as far as I have seen.