Scafool,

I too apologize. I have the kind of personality that gets egged on a lot, and as a consequence, I have long held the reputation for quickly biting peoples heads clean off, so to speak. It's not personal, only a matter of respect; a personal aversion to feelings of indifference; an intolerance of certain kinds of strange criticisms.

I agree that plant leaves should not form the mainstay of a survival situation diet in terms of calories, but they do provide an abundance of nutrients (vitamins, minerals) that might prove to be just as important as calories, in little ways that might not be so obvious, and in certain situations.

I think most Americans have enough body fat, that for the few days or even several days that they might be in the wilds without food awaiting rescue, they are not even going to come close to dying of starvation, and a few daily handfuls of edible plant leaves might be enough to stave off the hunger pangs until the fat reserves are gone, which could be quite a while for some heavies. If edible plants are available, I would rather stave off the hunger pangs, while losing the fat reserves as I await rescue. To run around chasing rabbits would burn so many calories that I might then actually need to eat them. You thin guys and gals are a different story, and I hope you can catch them.
When the fat on our bigger bodies is finally gone, though, especially if on the move, and if living off the land for any extended time, meat is certainly essential, but so always will be plants.

Another consideration is for their medicinal value, and of course their utilitarian value.

For example, not only is plantain a widespread and common edible, it also stops bleeding.
Not only does cattail have starchy edible roots, the leaves can be weaved into baskets, and the fluff is a great inside the pants insulator and also a tinder.
All pine (Pinus) trees provide edible vitamin C rich needle-leaves, and strips of the inner bark can be made into cordage.
Willow shoots are made into baskets and fish traps, and the bark has salicylic acid (aspirin) in it.
The bitter tannic acid in acorns (edible) is also used to preserve leather, and as an antiseptic.

When looked at this way, plants are seen as indispensible, not only to survival, but also to wilderness living.