I mean much of their work is building a public profile as a "thought-leader", and making big bucks speaking at conferences and advising large companies when in reality, they have no experience of building anything with the technologies they hype, and often no real technical understanding of those technologies either.

I am not saying this is the common case. Naturally, there are many brilliant people in our industry. I am however saying that this happens enough for it to be a concern of mine.

As tempting as it is, I won't name names.

I'm not the OP but I would guess it's because most of the tech leaders aren't there because they did something great and are all knowing, but more because they were at the right place at the right time and met the right people. You could replace any of those people with 10,000 other people with similar qualifications and they would do just as well.