It would be an interesting survey for sure. I am not an artists, but I will give my intuitions for the results I would expect. As a note, I mostly watch commissioners as I usually like a theme more than a style.
- I would expect no money, at least at start. Think about it like athletes and sports, most do it for fun, a few do it for some money, and only a small amount make it as a living.
- For those that try to do it full time, I see a lot of burn out. I have seen many try to do a drawing a day, sometimes as patreon rewards. This usually doesn't lat more than a year before burnout. I've seen both transitioning to art as full time, usually after a patreon threshold, as well as moving art to a side hustle after getting a more traditional job for a more sustainable income.
- Based on rough math, I have seen about $30 k - $115 k, although the higher end is usually game related. https://www.patreon.com/ruaidri , https://www.patreon.com/fek , https://www.patreon.com/caroo . Both ruaidri and caroo do commissions and other project as well. I usually see the transition to art full time after a sustainable income is achieved, not before.
- See previous
- I would assume networking is a big part of this. Trades with big artists, pushes on social media, presence at cons...
- No real intuition, but I would assume if its doing commissions, its work, if its opening a patreon to continue working on personal projects, its not.
This is all just based on intuition and looking at it as a skill field like any other.