I've read the entire thread, which raises a very interesting question. As usual it doesn't comes to an answer... Not a fail from the posters tough. Nobody knows this answer for sure, never will and the ones that says they do know fails on the light of the ages passing by. It looks more like this:
That being said, I think the deal is far beyond readers vs. paperback environmental efficiency. The deal, imho, is the human scale, being the scale the headcount.