For many years I made Halloween masks as a year-round, full time job and I have recently moved into dealing in digital art.
I can only reiterate what everyone else here has already said in one way or another. You can make a living doing this if:
1) You love what you’re doing and would be doing it anyway, even if you weren’t getting paid
2) You’re prepared to work long and hard hours
3) You do your due diligence on all your projects: dot the T’s and cross the I’s
And there is a lot more to it than just creating the 3d pieces. So much is market research and accounting. Know your audience. Find voids in the market that you can fill. Do it better than everybody else (at least in your own mind). And know how to value your own work. When I was selling masks, so many of the other independent mask makers would make a new piece and put it up for sale for $200-$300 without any thought to why they were charging that. They’d sell a few, sometimes quite a few. But I did the math and calculated all the overhead and man hours, and realized I could produce the same thing for $50-$60 at retail. And I sold a ton, almost more than I could make by myself, some months.
So talent and ambition are drive are a huge, huge part, but you also have to be smart and aware that you’re not working in a vacuum. As well, there is a component of luck involved. Perhaps most importantly, you have to keep plugging away!