You are missing one thing: Working for yourself is much easier psychologically in terms of motivation and energy. Burnout is less. Compare that to a corporation where you need to do what you are told and report to people who manage your day to day work. The difference is too great.

Indeed, for content creation things may be very difficult since it requires more effort than other fields to be successful. However for many other fields, from marketing to programming, its much less of a problem.