In exchange for that, you take on the high risk of only having 1 business paying you at any given time, and only learning about the world via 1 business. If something goes wrong with that business, or they end up doing things in a way that is not relevant to the wider world, you can get screwed.

I think part of the reason is that freelancers actually do the work; they write a proposal, and then three months later people check what they produced.

So called "white collar" employees, for the most part and in my experience, pretty much sit around doing, well, nothing. They go to meetings, talk on the phone and check out the work produced by various contractors, consultants and trainees, drink gallons of coffee, and that's pretty much it.

This is of course a generalization; people who have physical jobs (moving things or making them) are in a different category, as well as people whose output is somehow monitored, etc.

But in many many big companies there are swathes of people who would be hard pressed to account for any of their day.

And they still get paid, and they still have a job, and they still have colleagues. That's something.

One advantage corps have is teamwork. (Maybe I need to get in on some kind of mastermind group.)

Also, the studies might indicated breakdown by profession and how it changed over time... Programmers, graphic designers, writers, etc.

“individuals who have engaged in supplemental, temporary, or project- or contract-based work in the past 12 months.”

That's very vague and broad. I mean even restricting yourself to "real/full-time" self-employed, you'll find out that many truck drivers, most mechanics, most hair dressers, they're all 1099s...