The key here is managed expectations. Access, for example, has done quite good as a tf artist with a patreon. He makes about a thousand dollars a month which isn't enough to live off of but is more than enough to keep him drawing and certainly helps.
About once a month he releases a peice of artwork to the public and just about everything else he draws are requests from his patrons. You have to donate to be able to see them. The more you donate the more requests you make. Better quality requests too, from pencil to ink to full color.
That's the sort of stuff you have to do as a patreon artist. You have to give people a reason to support you, prove you are quality, let people interact with you, and understand you'll only get so much money.
https://www.patreon.com/accessworld