So how does Author Solutions make money? It is, of course, publishing with print on demand (POD) technology, so its up-front costs are much lower than the traditional model. And, of course, it's not paying any advances. But still, to make enough money that it can afford to buy up the competition, Author Solutions probably makes money off of its authors every bit as much as off its authors' books.
Self-published books tend to cost more than mass market paperbacks. Lulu, for example, doesn't offer mass market as a format, only trade paperback. Self-published authors thus encounter price hurdles as well as distribution hurdles in reaching their readership. I think if I were going to try the self-publishing route, I would go with CreateSpace from Amazon, just because my books would then be able to blend in (somewhat) on the Amazon platform; presumably, they could be sold as Kindle ebooks, too, which would be one of the few ways a self-published book can achieve the same level of instant accessibility that most books have.
No one ever said getting published would be easy—or if they did, they lied.