Here's my experience in the most indie gamedev world:
I started making pixelart many years ago for fun, but not daily (not even close) and not with the idea of earning money with it until two years ago when I decided I was able to make stuff for games.
I've been working on games since then and I've rarely earned more than 300€ in a month. And there are many months that I don't see a dollar because either I finished a project and can't find another in some time, (there are months with lots of new offers and months with barely any offer. And you don't get every job you apply to, or it's bigger than you can handle, or you're just not good enough for what they're looking for...) or because something happened and didn't have time to finish when I wanted...
Most of these games aren't even developed by studios or many people. It's just a programmer with a low budget from their dayjob and wants to make a game that most likely will never be finished or released
And they usually pay per sprite and not by hour, which can be both better or worse. I've made lots of money in an hour some times and also less than I wanted other times.
I get burnout very easily so I usually don't spend more than 2 hours a day pixeling lately anyways. It's rough when you make stuff because they tell you and you don't really like it, at least for me. I'm a bit lazy too heh.
So I could earn more but not always, because as I said, there aren't too many offers that fit you every time.
Here's something from my first little job for reference
(click to zoom in, ctrl+click to zoom out)And one of the latest
I guess that's where most of the people start so I hope it's informative. Anyways I'm not sure if you should be thinking too much about that stuff yet.
What a huge post
Keep pixeling