I think donations would work, if there was not all the spam content to sift through. Imagine if all that spam was not financed or pushed by ads and marketting, how many more users would feel the need to find good content, rather than sheeply accepting whatever is pushed into their faces. If there simply was not so much of artificially pushed meaningless or generic content, then their need would move to other content. If that need was not fulfilled, then the demand would outweigh the offer and more than enough money would be available for donations.

Perhaps an example, not sure if that one works well: I have my personal music collection. I choose music to listen to based on mood. I do not own a spotify account and I do not want to own one. I go out to my music collection and choose music for myself or I go online and search for more music of some genre or fitting my mood. I actively seek that out. On spotify people let stations play some music, based on algorithms. The content is pushed into their faces (ears). If there was not so much of music "to fill the gaps", then more people would go on an active search, instead of relying on it being pushed to them. They would maybe discover some music from some composer and seek out their website, shop, bandcamp, whatever, and buy their music there. I have done so at least and found great music this way. Basically cutting out the content pusher middleman, that has nothing to do with the actual creation of content, but merely acts as a publisher. More people being actively seeking content themselves, less people relying on publishers.

I guess it is a continuous fight of donation financed content creators against the generic artificially marketted stuff, that is financed in different ways. We can however see, that there are content creators out there, who do make due on donation basis. Personally, I hope that we will see more of that and less affiliate marketting pushed stuff.