That's the gig companies' marketing, not their intention. The intention was to get cheap, disposable labor. In the US and other developed countries, an employee has a lot of rights and an employer has lots of responsibilities, so under-paying and firing employees is pretty difficult to do.

If a business model only works if you under-pay and mistreat workers, someone (e.g. Fedex, Uber, US govt, and even Microsoft) will fin a way around it by misclassifying employees as contractors.