a. Concepts like "assume good faith" and "civility" are at the core of what we do for a reason. Please don't poison the discussion climate. It is perfectly possible to discuss potential conflict of interest in a way that is in line with Wikimedia norms and expected behavior.
b. A fair chunk of the development time lies at the feet of the WMF, when the old solution was breaking down, the new renderer couldn't effectively handle collections and the Foundation, looking at the number of people who were using the books-to-PDF solution, couldn't justify taking people away from other projects to work on it.
c. I suspect you vastly overestimate the long-term financial viability of discouraging the use of collections if one's business model is printing collections of articles. The typical reaction to not being able to generate a PDF in the way one had hoped is to not generate the PDF. Printing a book is rarely a reasonable alternative to downloading a PDF. PediaPress stepped in because they want this to work.
d. The developers have to do other work that's actually putting food on the table.