Publishers range from those who were first to make a bet—and some big bets at that—to those who are still standing in the background watching, or even outside catching a smoke. There seems to be room for all to be successful.
None of this is to say that e-books will not be a major, if not even the predominant format for content in the future. For some readers (and publishers), it already is. A whole other aspect, as Mobed points out, is that the e-book is just one element of digital content distribution. For some publishing segments, other digital formats have taken off faster and more furiously than e-books.