Publishers are, in a sense, gamblers, especially those who pay large advances. They speculate on the unknown and untried in hopes their gamble will generate enough return to pay for their investment plus a profit. Publishing is, after all, not a charity but a business.
With an advance, most authors feel they are already successful, so it’s felt the publisher who paid their advance will do everything necessary to market their book. It’s easy to assume this as to do otherwise would seem foolish after making a large investment.
What most authors don’t realize is if their book fails to make back monies paid them in advance against future royalties, their publisher has little incentive to publish that next book. So if the book fails, in many cases, so does the author’s future.
Wise authors who have gone on to be continually successful realize marketing is essential and something everyone who participates in the process MUST do. If there is any doubt about this, there are many, many examples of those who thought otherwise and failed.
It’s also true small indie publishers who don’t pay advances can take bigger risks. However, also true is the fact that if little or no promotion is done, both author and publisher fail when the book fails. So rather than stand around wondering whose job it is to market, doesn’t make sense to take it upon yourself to make sure someone is doing it?