We are not talking about a service here, we are talking about OSS codebase and in my experience it does work.
IMVHO, these are the same thing for the purpose of this discussion -- providing something to others, free of charge.
> and in my experience it does work.
Good for you (no sarcasm meant). But sadly this doesn't really seem to 'scale' that well.
And what I've heard from other maintainers is that Borg seems to do comparatively well.
So no, if you think in terms of payment, donations do not work in the open source ecosystem.