If we didn't have critics we'd still have kings with divine right. This seems like an exaggeration, but it's really just to say that we need people to look at things critically.
I haven't collected any evidence, but I wouldn't be surprised if those who find success are always looking for reasons why something will work, and those who run into failure are always looking for reasons why something won't work.
This isn't that far from prosperity gospel preaching. Believing doesn't make things happen, otherwise NeXT would be dominating the industry and not Apple because boy did Jobs believe and give it his all.
Sometimes smart people are wrong, and it doesn't hurt those people anyway if dummies are discussing their work.