but it’s not really viable for the internet as a whole right? Hoping for some spare change from a tiny fraction of your visitors
Why not? It works for kbin/lemmy instances. It works for Wikipedia. It works for Lichess.
Sure, some things like video hosting are going to require a lot more bandwidth / server storage so perhaps those need to be subscription based but I think large swathes of the internet could be turned into a donation/subscription model. it just isn't done that way because it's less profitable.
look at which video games are the most profitable - it's always the free ones. fortnite, league of legends, etc.