There's this story from Freakonomics: A Kindergarten in Israel started to charge a fee for parents arriving late to pick up their children. Result: More parents would arrive late, because paying a fee was less of a burden than the bad conscience they had previous;y had when they made the employees stay late.
This would work in reverse. That good feeling I get when I contribute a patch for some random project I improved at the margins would be devalued by whatever $0.29 I'd get wired at the end of the quarter.
You hit the nail on the head what troubled me about my own suggestion of easy monetization but could not quite put into words.
Perhaps the few poverty striken maintainers are necessary outliers in this equation. I still feel irritated there can't be some simple opt-in value capture program for recognized bdfl's.