There’s a gray line here that government cannot afford to clarify. If you’re a subcontractor you get all the business advantages of a sole proprietor which include major tax cuts and a lifestyle improvement not available to the highly regulated and taxed employee.
Employees are treated like children and their allowance is managed by the corporation to government’s benefit. A sub can write off a whole lot of costs before claiming a salary.
Technically, today, it's more common for people to be wage slaves -- no one owns you, but no one cares for your needs (except yourself), and your labor is yours to sell, but it's a buyer's market.
In reality, we are all government slaves -- owned and controlled by the state, our needs somewhat met by Social Services, our property is not our own, and our labor is thoroughly regulated.
Uber is an example of free labor which allows people to work gigs and control their own lives. There are downsides. But (in theory) individuals have a good amount of control over their own lives. They are not slaves of any kind.
Big Business and Big Government hate Uber.