The book points out that "amateur" posters and even book authors often make little money from their work, because the host companies often keep most of the revenue (whether ads, for from book sales, as with supported self-publishing). On the other hand, most "amateurs" would not be able to get conventional trade publishers or movie studios to "publish" their work at all.
If I had to "compete" in a normal way for "influence", by, say, running for office (which people have asked me why I don't do it) and asking people for campaign money, would that be morally better?
Wikipedia attribution link for Rochester NY aerial. My last visit was in 1992, as I recall. Author is Chris Tomkins-Tinch, CC-SA 3.0 license, unported.