I actually know some people who are working as freelancers as a full time job. It depends on what someone is doing actually because when you have a good portfolio which can easily fetch you money as a freelancer, it's easy to make it a full time job.
My freelance job is a side job, I still don't earn enough to be able to live from it full time, if I lived in another country maybe I could, but the cost of living in my country is too high to still live completely from my freelance job, maybe in the future I will be able to get it or I will move to a country where I can work remotely and my freelance job covers all the costs.