As LATBR editor David Ulin says to Poets & Writers in this short interview about book reviewing, what gets chosen and what has to be written about:

Is there a risk of becoming a shill when you’re obligated to write about the newsworthy books?

I think there’s always a risk of becoming a shill for the book industry. It’s the obligation of editors and critics to remain vigilant and aware of that. I do agree that there’s an interesting discussion to be had about how and why certain books and writers get identified by their publishers and publicity departments as the [ones] to push. But you don’t give those books a free ride, you still critically engage with those books in the way that you would with any other book. I will also say that, especially in a section that can only review twelve hundred or so books a year, not covering a book can make a statement as well. There are instances where you might want to consciously skip one of those books, or any book for that matter, and in so doing, you send a signal.

The question is, how often are such "signals" taken by the publishers whose books get ignored? Though I do think the concept of literary triage is a fascinating one, if deserving of its own post altogether...