I am just rambling and do not know if what I am saying is really valid. Others will tell you the real scoop.
My guess is that PROFESSIONAL PUBLISHING, by definition, is something more than the author getting their work out. There has to be others in between the author and the publication, the publishers themselves. In the old days, there were EDITORS involved in the process, but from what I understand, there is little of that any more.
Also, professional publication involves the publisher handling the expense of printing and distribution. For it to be a professional publication, money should always flow TO the author.
Actually there are two filters in the publishing world for quality. The first is the agent. They filter the product because they are selling it to publishers. Then the publishers use editors (from what I can gather listening to published authors they still do that) to filter further because they are selling the work to the public.
When you self-publish, those two filters don't exist. If your definition of professionally publish means going through those two filters, then no, you're not professionally published.
I think the agent/editor part of the publishing process helps give the reader a confidence that the book will be at a certain level. Self-publishing, to me anyway, means the quality of the work is a bit of a crap shoot and should be priced according to the risk the reader takes.
The professional publisher also knows how to market their books and most self-publishers probably don't.
Makes sense. My idea was, if I cannot sell my writing (never tried yet) to an agent/publisher/whatever, is it ever better to try and sell it myself? Naturally individuals don't have the expertise, resources, or money to market their work a hundredth as well. But maybe it's better than nothing.
If your work becomes popular on the istore (or whatever) just based on word of mouth, then perhaps publishers might want to acquire it? Or would they still be put off by not having first print rights?