I would attribute dropping out of HS/college more to laziness, apathy, or not wanting to be part of the traditional system, not anything related to intelligence. Its not because I know a lot of intelligent HS dropouts, but because I know TON of stupid people with college degrees. I mean like people working minimum wage crap jobs and not trying to change their life, despite having a bachelors degree.

Curiously, in the past few days I have seen several articles about the "hidden economy of unschooled people". I guess the fact that those publications all chose to use the word hidden in the headline echoes what you say, but now that it has been widely reported and is equally fresh in the minds of the public, it is strange to see that they still hold on to those legacy ideals.

It's not curious, it's called "pinning": Articles that are tangentially related to some popular interest topic get readership for that topic as well as the subject of the article itself.