I’m almost 2 months into a project which essentially boils down to an iteration of Asteroids & have a demo up on Steam, but while I’m really pleased with it so far, I’d be surprised if the game even makes $1,000 at this stage, let alone $10,000. I’d be very happy with the latter though as I’m treating this very much as a learning experience, not the least in terms of getting my head around the marketing & community building side of things.
I’ve also worked on a game which I’d consider to be a “modest success” that took 2-3 years with a friend & sold enough copies for my share to so far pay (almost) £24k/year, which as others have mentioned isn’t exactly a competitive salary for a software developer generally.
In particular, while I can probably build small games in the 2-3 month timeframes suggested (especially if each is an iteration on the last), don’t forget all the “marketing admin” & trailer making & so forth. That’s also definitely not enough time to build enough wishlists to get any Steam visibility etc.
Still, definitely timely food for thought for me personally!