Depends on one's motivation. I really doubt at any point the Dwarf Fortress guy expected to become a millionaire with his game anymore than Notch expected to become a billionaire off Minecraft. They pursued the ideas because they were doing something that they themselves wanted, and enjoy(ed) making.
There are other examples like UnReal World [1]. It's a game about surviving in the wilderness in Finland made by a guy living out in the wilderness in Finland. It had its first release 31 years ago, and the dev is still going at it. He's not exactly rolling the dough, but what's better than doing what you enjoy and making enough to get by doing it?
Well sure, making way more than you need! But spending the prime of your life doing something you love with the chance of a nice payday, seems more pleasant than spending the prime of your life doing something you dislike but with a more guaranteed upper mid payday.
The success of DF should be viewed as the result of perseverance in coding and dedication to a community. They are pretty much the OG of their niche and have spawned thousands of copies but the copies have been the ones to fail for the most part mainly due to not sticking with it and/or not building a strong community around their projects. DF survived pretty much in spite of the actual product itself which, while it has improved steadily over time, remained almost actively user-hostile with its UI. You had to really love the game and the community in order to play it regularly. The Steam release is really a crowning triumph that will hopefully ensure the legacy of the game if not a completely renewed life.
It is absolutely possible to succeed as a solo indie game developer, even if the likes of Minecraft or Stardew Valley or Dwarf Fortress are pretty extreme outliers. But it's nice when they do succeed.
How many of those failing 80% were working as hard as the Tarn brothers or Eric Barone? I'd be surprised if 1% of them were.
Luck is a big factor, but working hard is an often underrated component. Equating game development, or anything in life, as a lottery is a terrible mindset to be in and sets one up for failure and mediocrity.
Success lies somewhere between cutting one's own losses early, and unrelenting stubbornness.
I'd say even that is generous. Especially once you consider opportunity cost -- length of development, contractor expenses, hardware, lost potential earnings if employed, etc.
My VR game eventually sold 130k copies over four years, but amortized over 1.5 years of development, $100k contracting expenses, $25k hardware, most copies sold at sale price, and another partner to split earnings with I still would have made significantly more as an employed principal or even senior engineer.
As far as indie game success goes, selling this many copies puts me on the far end of the percentile scale. Oof.
There is of course the non-monetary "compensation" aspect. I created something I am truly proud of, tons of people have either seen or played it and enjoyed the experience, and I crossed a huge item off the ol' bucket list. Even if the game had only sold 10k copies, I still would have called it a win personally.
yeah this is 100% survivor bias; their success only means you can make money with already hugely successful & popular projects, it's not indicative that your project will be successful or that you're doing the right thing
but it’s an example of someone following through and bringing something to fruition, not to imply it means you’ll get the same sales and reception but working 15 years on a project is an insane extreme, if he can do that I can do a year or two just to say I finished it
