Now, I want to first point out that i think it's possible to dominate a niche market and not be seriously affected by piracy. But that would only work if the niche is small enough that it doesn't attract the attention of a pirate.
In general, you can't effectively monopolize a digital market. At least, you can't do it in a way that will hurt the customer. Raise prices too much and you will simply drive people to piracy.
I also don't think it's possible for a middle man to dominate publishers (not anymore). It is simply too easy to create a new distribution channel these days. There are tools for making a webstore readily available online which range from moderately difficult to idiot proof. There's no reason publishers can't sell their own content.
If you're going to say that you can't get people to come to your store, then you need to take your store to them. OPDS now supports in-app sales of ebooks and digital content. You can even sell ebooks from inside other people's apps, not just your own. In fact, Aldiko already supports this.
image via Flickr