That a counterexample exists doesn't really impact the claim that "many" (though they imply "most" imo) do not work this way.
Indeed: Not everybody is the kind of person who pays for Jonathan Coulton's music instead of downloading it for free.
RTJ also have an established brand - I can tell you 100% I only know of them because of their previous marketing, I've maybe heard one song. It's like how Radiohead did a pay-what-you-like for their album and it came out being viable, it only works because of their previous commercial success through more traditional routes. If they'd self-produced and made Pablo Honey PWYL they'd probably be unheard of.