It seems clear at this point that, particularly in genres like romance and science fiction, e-books are cutting into print sales.
Right now we’re in a transitional period where books are simultaneously published in both formats. But, as Eoin Purcell has observed, drawing even a small percentage away from the average book’s print run makes the economics of its publication very difficult.
One solution, which I don’t think Purcell considers, is to price up not the print book but the e-book, to compensate for the skewed economics on the print side. So far, despite some grumbling, there hasn’t been very much sign of price resistance to e-books. Once you own a reader you have a natural motivation for filling it with content (or else your purchase of the reader feels foolish). Of course, if one group of publishers’ prices get out of line with others they will have a problem. Just another area where big corporations have a clear advantage.
In the long run, more books will probably fall into one side or the other — many books will be published in e-format only (not much need for a physical copy of that disposable romance novel). Then there are books like the kind I currently do, art museum catalogues. So far I’m not aware of a satisfactory e-format for such books. This also pertains to my own forthcoming title, 1616, which has a large illustration and layout component. If anyone can tell me how to make this into a good e-book, I’d really like to hear. Really.