It's the problem with leaning into a niche viewpoint. You have to continue to lean harder and harder into that viewpoint as the times change in order to keep the people who also believe in that viewpoint supporting you.

I genuinely think the FSF/RMS level hate of non-free software will continue to die out as everyone starts to die/retire from public eye. Whether or not that's a good thing overall is not something I'm going to touch, but it seems like there's not enough being this aggressive to keep this viewpoint sustainable.

It doesn't.

RMS could very likely retire today, find himself a nice seaside property, get himself a parrot, and sit outside in the sun in his pants and hack on emacs to his heart's content.

The only genuinely weird thing about RMS is that he doesn't do exactly that.

He continues to do so because he has to because of who he is. It is his calling. Zealots (and zealotry is not always wrong) have to do what they do. The same is true of artists. They don't continue to create late into life because they need to monetarily, they do because that is what they do.