I've been advocating the use of print on demand for new publishers and self publishers for most of this millennium. I've wasted a lot of electrons on this blog fighting over definitions, like the difference between POD technology and the author services companies that have sprung up around it, but all that now seems likely to go by-the-by as the new POD may just be renamed "Amazon printing." Tomorrow may see the "Buy" buttons for all of my titles disappear from Amazon, and if not tomorrow, next week or next month. If and when that happens, I'll put my title "Print on Demand Book Publishing" into revision to prevent new copies from being printed and think about doing a revision or a new edition. I won't play any games looking to restore my "Buy" buttons through back doors, I'm too crotchety a coot to knuckle under to the Booksurge crowd. But I won't call for boycotts or tell other publishers, and especially self publishing authors, that they should put Amazon behind them and move on.
The reality of the business is that there are only two real outlets for the majority POD book published by self publishers or author services companies. The main outlet or retailer for most of these titles is the author. Authors who choose author's service companies often forgo Amazon and distribution access to save fees, and the only sales generated therefore come through the author purchasing and reselling books by hand, or through sending customers to the website of the the author services company to purchase the books. While the number of books sold is not trivial due to the huge number of titles involved, the quantities sold for the vast majority of authors are non-commercial. Most may sell under 10 copies, but whether it's under 10 or under 100 matters primarily to the author and the readers, not the IRS.
The second major outlet for these books is Amazon. Amazon lists all of these books for sale, and Amazon is the world's biggest book retailer. Most self publishers labor under enough difficulties; lack of experience, lack of marketing, non-commercial acquisitions process (ie, writing what they want) and limited resources. For a new self publisher to ignore the biggest book retailer in the world, and the one that will absolutely stock and sell your books if you play by their rules, would be self destructive. While some self publishers may be rejected as too small by Amazon's Booksurge printer, they can sign up through Creatspace for POD or go through Amazon Advantage and supply books printed any way they want. Even though Advantage requires 55% discount and the publisher pays for shipping, it's still a decent deal by industry standards. It's just a different economic approach than the short discount publishing I first described five years ago, but it has some compensations in flexibility of book design to offset some of the financial drawbacks for a serious publishing business.
But lest you read this a defense of Amazon's practices, there is the other side of the coin. While Amazon is not a monopoly printer of print on demand books, and I'd estimate they have a low single digit percentage of market at the moment, I believe they do hold a disproportionate share of the retailing of print on demand books. I'm one of the few self publishers using print on demand I know who has been able to get some stocking of a title in bricks-and-mortar bookstores by way of regular distribution channels (Ingram). Self publishers as a group are hugely dependent on online sales, with most of the self publishers I know getting 75% or more of their sales from Amazon. For publishers like myself who count on our own websites as our marketing platforms, we can certainly shift a proportion of our sales elsewhere, though we'll lose out on the multiplier effect that made Amazon our first choice. But most self publishers have no marketing, beyond their use of the Amazon platform. Not having their books listed with "Buy" buttons on Amazon and possibly disadvantaged in their visibility as well will be the end of any hopes for real sales success they may have. I cannot over emphasize that Amazon isn't just the world's biggest bookstore, in my estimate it is the dominant retail platform for the sale of self published books.
I'm confident that my own publishing business will survive with or without Amazon for as long as I care to continue writing and selling books, but that's because my business model has always been centered on my website rather than Amazon. If Google decided tomorrow that they were only going to send visitors to websites that paid Google to host the sites in order to "better serve their users", I'd be in serious trouble. Putting all your eggs in one basket may maximize chickens over the short term, but nobody I know would recommend Blanche DuBois as a business planner.