To answer your two questions:

Question - "Besides, how many people - including Olsen himself - would be capable of surviving in the Great Basin desert, or the Northern Boreal Forest, for a full 12-month stint?"

Answer - I believe thousands have done exactly this as this was home to many primitive Native Americans for many generations.

Question - "And how many of them would be able to do it based on the information contained in a paperback book?

Answer - IMO NONE! <img src="/images/graemlins/tongue.gif" alt="" />

And as a side note. None of the information in any book I have seen will "make" you a survivor. Any research and/or book learning must be acompanied by good old fashioned experience like what we call "primitive camping" in the U.S. (or at least here in Texas). None-the-less, IMO, the skills taught in this book are solid and it also not only an informative read but an entertaining one as well.