Remember the plethora of books over a decade ago about how to make money designing web sites? Have you seen the non-stop parade of "advice" books on how to make money with social marketing? It seems that everyone who has somehow managed to have a little success at something writes a book on how to do it - and most of the "advice" is useless.
Here's the short version. If you don't already know the details of what is being offered here, you're probably pretty late to the party. The real story is that self-publishing is no panacea and requires a lot of time, expertise, technical knowledge and marketing savvy - something that many writers eschew and prefer to leave in the hands of a publisher.
But, the publishing world is upside down right now so advice books will continue to proliferate. This is not a condemnation of self-publishing, far from it. It is however a warning to any writer or author who thinks self-publishing is a quick path to riches after reading a self-help guide.