That sounds very interesting, I'll take a look at the book. I actually posted something related to your point about authors asking for payment only a day or two ago. Feel free to take a look at it if you've got the time. Other than that, I agree with your point. However, the article, in my opinion at least, is less about asking for payment and/or sponsorship, and more so about having no opportunity to rely on some support in the first place, be it from wealthy family members or a job that conveniently allows you to write all day while paying your bills. Writers and artists should take the donuts when they are offered, but unfortunately they rarely are. It doesn't in any way diminish the art itself, but if one were to go into the field expecting donuts to be offered to them outright, I'm afraid they'd be in for a rough awakening.
Actually, this is my point (and Amanda Palmer's): Artists are really bad at understanding when they are being offered donuts. They are also really bad at accepting the donuts. I have spent the last 20 years working with artists and arts organizations, and it is astounding how blind artists are to the opportunities that are being thrown at them every single day. And how reticent they are to accept the proffered donut. Accepting the donuts requires the artist to understand they are being offered a donut, it isn't poisoned, they do deserve it, and accepting the donut does not compromise their art in any way. That's a big part of "The Art of Asking".... teaching artists that it is ok to ask, and to receive. Writers and artists should take the donuts when they are offered, but unfortunately they rarely are ...