Sorry about that 'backstab' from earlier. English is not my native language and I didn't know that this word may have such negative meaning. It just boiled my blood when I saw that a project for which I was hoping for many years (since good old Detroit possibly?) is taking a turn only a bit better then shutting down - from my point of view of course.
One thing that Daffyflyer mentioned seems to clarify things for me. As I am not much into a multiplayer in general, I didn't realise that this may be such a big problem. Yes, I see that going for Steam may be the best solution here - not too hard and still of good quality. And if there's a chance to get the launcher only limited to single player then I'm into it.
Do you sell e-books or normal ones? Because there are a lot of differences between physical book (or any other good) and any e-thing, be it a game, book or picture. From my past experience I can tell you that very few people can handle it. One of the most silly things I heard were words of some book publisher about e-books. He was wondering how can they be cheaper than normal books if he have to manually scan the book, then convert pictures to pdf or something and then publish it - that's a lot of additional work, isn't it? Quite obviously he didn't know how printing a book looks today, poor thing.
And as we're about the middleman problem, there are cases when such agent is needed and cases when he's not - and I see the latter ones just too often.