Sometimes self published material is good. But way more often its not very good.
Yet, often publishers don’t put stuff that is very good on the market and to me, leaving it up to the buyer is the right thing to do. Publishers can take a personal view of the product, not taking into account that the story might in fact appeal to people. If the publishing company doesn’t put in real effort to publish this, then I am certain that the book won’t do well even if in fact the story is great and just needs a good boost.
Frankly I don’t believe that publishing companies take advantage of real talent and completely rip off the authors. Only paying a dollar per copy sold is a complete cheating of the work that the author does who should be getting the majority of the profits.