Why does it matter? Are you thinking of buying stock in Kodak... or Sony?
Change is the only constant in the universe, so film can't possibly stay dominant forever. We're clearly in a transitional phase or else you wouldn't have even asked the question.
Almost everyone admits that someday, digital will be the dominant format for origination. The two debatable issues are how long until that happens and whether film will continue to exist as a niche market if it can't maintain its sales figures, or if it will disappear.
I could say that it will be about a decade until digital is the dominant format and film is a minor player in moviemaking, but that would just be a guess. I'm not sure it matters much -- we have to live and work in the here and now, and at the most, project the technical future two or three years from now (if we are thinking of investing in equipment.) Beyond that, it's mostly academic.
