Check the donate page of certain projects Krita and Gimp doesn't even have option for bitcoin, just to give you an example lol and if you search for Krita there was a Tweet not long time ago they were ranting about is bad for the environment climate change shiet. So you can guess another reason people not doing it. Ah.. an their CoC thing showing lol.
Discussion
This applies to everything free though - including Nostr. When the early investors (all individuals for the most part) run out of funds they are willing to drop into this, there will be a crunch.
Linux, SimpleX, Libre office suites, browsers.....
The issue is everywhere. The people are not willing to pay to maintain leverage, then act shocked when corporations end up with the leverage.