I see that my good friend John Scalzi has posted a bit about Yog’s Law.
Self-publishing is its own thing (and I’ve been self-publishing since 1978 or so). Yog’s Law (“Money Flows Toward the Author”) is entirely valid there, too, despite the continual attempts by scammers and flim-flammers to obfuscate the obvious. Self-publication is a subset of commercial publishing. If you, as publisher, can’t afford to pay yourself, as author, 10-15% of the cover price of each copy sold, you can’t afford to self-publish.
Note that true self-publication is different from throwing money at one of the vanity presses which, without changing their business models (or fee schedules) in the slightest, have re-branded themselves as “self-publishing services.” They’re still vanity presses and fall in the vast grey area between A Very Bad Idea and An Out-and-out Scam.