Are People Really Self-Publishing Millions of Books Each Year?

Recently I was surprised to read that the number of "new" books self-published annually was in the millions.

Why?

My conjecture (it is hard to get beyond that given the paucity of data and analysis out there) the self-publishing boom we saw circa 2010 (when e-book readers arrived on the market, when publishing services like Amazon's came into the business) prompted a Great Drawer Clearing. Meanwhile, deceived by our "success story"-addicted media, a great many people who never had a chance of becoming authors the traditional way fancied that maybe they could make a career this way.

Still, much as agents and editors and anti-populist critical snobs snivel about "everyone" thinking they are a writer, there was only so much stuff in those drawers, with the most likely candidates probably putting out the most likely stuff first. At the same time those who had been gulled into believing that some revolution was here, the power in the hands of the authors, quickly learned otherwise. It was not a case of "Publish it, and they will come." Rather you published it and it just sat there, very few self-published writers selling anything to people who were not friends and family (I dare say, more than usually supportive friends and family). There was thus less apparent incentive to bring out old stuff, let alone write new stuff--less and less all the time as the market grew ever more cluttered while people read and read less, supply and demand moving in opposite directions, with the limitation of the e-books so critical for the self-published to a relatively small part of the market, and the unrelenting hostility of the gatekeepers toward the self-published not helping in the least, among much, much else that made the road steeper rather than easier.

It seemed to me the case, too, that young people have been less inclined to dabble in long-form writing than their forebears (with, indeed, the "decline" of the English major seeming to me to reflect decreasing interest), while people of all ages seem to have been devoting time and energy to activities very different from writing books or anything at all, to a much greater degree than even a few years ago. (Wanting to express themselves they "micro-blog" on Twitter, or vlog on YouTube, rather than "blog" in the old way.)

Nothing I have yet seen has convinced me that this picture of the situation is inaccurate--while the aforementioned figure can conceal a lot of ambiguity, given that it is less than clear just what counts as a "book" (a lot of self-published work not even purporting to be that--short stories sold individually probably lumped into the figure), let alone a new one (given the ambiguities of reissue with self-published work the author can edit any time). The result is that I can easily picture, for example, the number of items that resemble what most think of as books hitting the market for the first time in this way in any given year as rather smaller--with the kind of decline I have talked about not ruled out.