I think this is just common to the whole game industry - not just indie games on itch: Most games do not bring back what has been invested - even when you calculate just the minimum wage for the hours of work put in.
At the same time, their publishers also do not get enough money from these games to cover their costs. Especially when the publisher paid the gamedev studio for completion of the game. But they still succeed because of the very few games that have a huge success. So it is like from 100 games
- over than 80 are a great or complete loss
- 10 are barely bringing in the money needed for their creation
- 7 are pretty good
- 3 are top sellers, also cross-financing the upkeep of the other 80 games from the worst category
But the Devs of the better 10 games will not have time to write here: They will be completly busy with bugfixes, customer support, preparing new features and content for the next update, paying taxes, giving interviews and many more.
I also donated to very few free games only and those 2 have been really successfull (also meaning: really good).
This is also, why I am keeping my fulltime job instead of going fulltime indie-dev: I keep my financial stability and can be a lot calmer and having a lot more fun than I would have, if my existence was depending on the success of my next game. :)