My data point would be Borg Backup, which, if you were to consider Bountysource to be payment for development, is under-financed by perhaps a factor of 40. 80+ % of funding came from three organizations.
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.
