Hell, I just saw an amazing open-source alternative to Raycast[0] and just replaced it the other day.
Solo founder here. My business is not VC-backed nor publicly traded, and I specifically avoided taking investment so that I can make all the decisions.
I avoid enshittification. This sometimes hurts revenue, but so be it. I wouldn't want to subject my users to anything I wouldn't like.
So, open-source is not the only hope. You can run a sustainable business without enshittification. The problem is money people. The moment money people (career managers, CFOs, etc) take over from product people, the business is on a downward path towards enshittification.
Even when I use proprietary software, I sleep easier at night knowing that open-source alternatives keep them honest in their approach and I have an out if things do change.
Stallman was always right, after all.
edit: oh, that and distributed authentication and distributed discovery