It sounds like Matt Yglesias is going indie with his next book (his last was published by
Simon & Schuster). Could this article be the prelude to the marketing campaign he didn't get from S&S?
How much his indie title sells could then be seen as a very partial test of the Yglesias thesis.
One problem with complaining about the marketing of your book is that the most obvious form of marketing, advertising, doesn't much help with books. At least, that's what Mike Shatzkin writes, and I'm thinking he knows.
Here's the only example I know of where one of the nonfiction authors I like has gone indie:
http://www.cringely.com/2014/06/04/decline-fall-ibm/
As far as I can see from reading the first chapter, and reviews, author Robert X. Cringely/Mark Stephens did better work under major publisher supervision. We'll see about Yglesias. And that's what it is all about to me. You can't tell me that publishers add nothing until I see their books are no longer superior to the those of the opposition.