strange. the areas surrounding vault city have a fairly decent fiber plant encounter rate. They are as abundant as apple trees (literally, if a map contains an apple tree, it most likely contains a fiber plant with some maps containing 2 plants.)
But as for the 1 fiber per plant thing...if an apple tree gives 20 fruit..maybe a fiber plant can be hit with that same developer's magic wand that makes everything give an insane amount of everything, with no cooldowns. I mean, resources have become so abundant that crafting is more a formality than anything. Honestly, if it got any easier, everytime you swing a sledgehammer, you would receive ammunition.