makes a compelling argument for:
A. knowing what plants are safe for consumption or
B. having a good guide for edible plants for your region.

Krakauer has an economic interest in promoting the notion of the life-at-the-edge vision quest, because that is what sells his writing... He seems to advocate a sort of Outdoor Magazine Philosophy, analogous to the Playboy Philosophy of the sixties... as if all of the previous bad decisions could have been redeemed by better choices at the end.