'Gig economy', in other words, freelancers/independent contractors.
It is a sector that is booming (in spite of California's attempt to squash it).
It isn't just for side hustle jobs like Uber drivers. Many professionals are moving into this for highly lucrative fields as they would rather work for themselves and set their own rules. I freelance on the side but have been very tempted to do this full time for years, especially as my hourly rate freelancing can be up to $150-$200/hour and I can set my own time, rules, and terms. Being at my company as long as I have I am hesitant versus waiting for a layoff due to a big severance, but also the ACA has made buying insurance an outrageous expense unless you take a pay cut and get subsidized.