If you follow the words of the UK's Society of Authors, you can disregard the rest of this blog, and for that matter, your writing career. But, you're not cookbook authors, you're business authors, and your ideas, your reasons for writing, and what your writing propels, is much different than fiction authors, etc.
Whether or not the digital revolution effects books the way it has music is yet to be proven, but nonetheless, business ideas aren't going to die, you just have to be creative how to make a living at them. But isn't that the case already?