Extracting fibers from plants (and processing them into Fabrics) is profitable only during the early, lower levels, when you have little to none access to items, which can be used in the deconstruction process. It is the simplest, yet at the same time the most time-consuming process - to be able to make even the lowest items (Light Armor) from Clothing, you will need from several to over a dozen processed Fabrics, meaning that if you want to create a single item, you will have to find and collect fibers from at least a fibrous plants. The main, and (at least during the early levels) the easiest, way to obtain fibers is to simply extract them from a source, which has a form of a fibrous plant - doing so, you will get from 3 to 4 fibers every time.
