...
He HAS to run out sooner or later.
It's like a monkey throwing its feces at you. Eventually, the monkey will run out of crap to throw, and producing more crap is not worth the effort, so he has to instead start throwing the bricks of solid gold that have been lying around.
As metaphors go, it needs work, but I think I've made my point. I'm willing to endure short showers of shit for an eventual 24 carats.