Before Amazon, Barnes & Noble and others opened up the epublishing business to everyone, a person who wanted to publish a philosophy book faced various hurdles (beyond the obvious one of writing a book). These hurdles varied with the path selected by the author: professional publishing or self publishing.
Getting a philosophy book published professionally was and is rather challenging. Philosophy books are generally not huge sellers (unless “philosophy” is taken to include self help books and various other dubious domains) and hence publishers are typically not scouring the globe for a new philosophy book. Publishers that specialize in philosophy books generally tend to cater to the academic markets and produce books for classes or for professionals in the field. As such, publishing a book in this area typically requires academic credentials (connections do not hurt). There are, of course, more popular philosophy books. However, publishers still tend to seek authors with academic credentials. There are, of course, exceptions-but they tend to be somewhat uncommon. I expect that this aspect of publishing will not significantly change, other than a shift in the medium from paper to digital (although I expect paper text books to endure for a long time).
In the past, self-publishing was generally not a great option. The author had to bear the cost of publishing the work (either directly or by getting involved with a vanity press). The author was also stuck with advertising and selling the book. While I am sure there are some amazing exceptions, what I have heard about self-publishing has been negative (the stories usually end with “and that is why I have 1,498 books in my attic”). However, self-publishing changed radically with the advent of printing on demand and ebooks. However, the most important change was the advent of Amazon’s Kindle program (and similar programs from Barnes & Noble).
Thanks to Amazon and Banes & Noble anyone can easily publish a philosophy (or any) book. This means that the field of philosophy (at least on these marketplaces) is open to anyone who can use a computer. One good thing about this is that the number of philosophy books will increase. Another good thing is that good writers with interesting ideas who might have been unable to get a deal with the major publishers will be able to get their ideas out there. A third good thing is that such books can be made available to folks who might not otherwise read a philosophy book. A fourth good thing is that it gives the author control over his destiny, at least in terms of his books. Even though I have a professionally published book, I rather like being master of my own works, rather than being a supplicant to professional publishers. It is, of course, natural to compare this situation with the Modern Era of philosophy: the printing press enabled new thinkers (such as Descartes and Hume) to get their ideas out there when the established academies were still often locked in Scholastic dogma.
There are, of course, some non-good things about this. One obvious problem is that self-published works are not subject to editorial review. While a professionally published philosophy book might be crap, it is at least reviewed crap. It is certain that the percentage of crappy books in the self-published field will be much higher than in the professional realm. A second concern, at least for academics, is that self-published works generally do not “count” and ebooks are looked on with suspicion by many in the traditional academy. Academic types, like me, are subject to the dreaded “publish or perish” in that we have to publish works in order to get promotions and tenure. As such, a self-published ebook typically will not help an academic advance his career (there are some exceptions). In my case, I’m already a tenured full professor, so I no longer have to worry about that (aside from looking good on my yearly evaluations). I do, however, have to worry about the bills-hence my new “career” writing ebooks. I suspect that there will be a gradual shift towards counting such books, much like some schools already give “points” for blogging.
In a nutshell, my rather obvious prediction is that there will be an upswing in the publishing of philosophy books, thanks to the blossoming epublishing. In the future, I assume that people will start referring to academics living in digital towers, rather than the traditional ivory towers.