I was just thinking that although I don't think von Mises' mal-investment theory is correct I in no way regard him as even remotely foolish. What's more, there are few (even libertarians) who were as committed to liberty as him. So Mises himself is very cool in my eyes. Interestingly both he and Popper were decidedly arrogant thinkers. Mises once told none other than Ayn Rand to her face that she was 'a stupid Jewish girl who didn't understand what she was talking about' and Popper has been called "the authoritarian liberal" because of the way he lay down the intellectual law about liberty. Other libertarian luminaries - like Hayek, Friedman and Nozick - have also been, shall we say, 'very confident in their opinions'. Rothbard was infamous for his intellectual arrogance which makes his case against Keynes' elitism a bit ironic.
Bertrand Russell - who knew just about every major intellect across every discipline and virtually every major country - regarded Keynes as easily to brightest of them all. Both Hayek and Friedman continued to have enormous regard for Keynes' intellect and his ability as an economist, and both were clear that he was broadly speaking a classical liberal - although both disagreed with his General Theory. It is nevertheless popular for libertarians to dismiss his thinking as obviously wrong and declare him an evil character. Keynes likewise respected Hayek but thought Marx was a quite a lightweight.
I note that Sowell was once a Marxist and he admitted to being one all through his student years under Friedman. Sowell is clearly a genius now but was he a moron as a student? I find it interesting that what turned him around was not any intellectual argument but his experience working in government when it became clear to him that government employees had no interest in whether what they were doing improved lives.
Popper too was once a communist. His conversion was also not intellectual. He became disillusioned because of the behavior of communists during a protest, specifically their complete lack of concern for the lives of individual workers.
Friedman was once an avowed Keynesian. Was he a fool then? I don't think so. What about Nozick, who to some extent recanted on Anarchy, State and Utopia? Did he perhaps become senile? I don't know but it seems that moron or genius status has little to do with the actual content of one's beliefs.
On elitism (not necessarily the same as unconstrained vision) - I think there probably are some people who could radically improve our lot through social engineering, just like there are people who could better serve justice by breaking the letter and spirit of the law and ignoring procedure e.g. the Alan Shore character in Boston Legal. I think Keynes (though not Keynesians) would have, and that Lee Kuan Yew of Singapore did, fit the bill (just my admittedly faulty opinion). The problem is that they form a such a tiny fraction of those who think they are part of that elite that they would be swamped by the Lenins, Hitlers, Maos etc. It would be disastrous to make it a rule to hand over power to elitists. In other words the institution of royalty is still lousy idea.even though great Solomon like kings have existed. I wish I could say that democracy is a great way to weed out the bad and yet give the best a chance but sadly I don't believe I can.