The same goes for crafted materials. Woodworkers can make about 10 different handles with one recipe, and each handle is used in one recipe... so for them to be able to sell handles they need to know who is looking to make what and which handles are worth the most... Not to mention that the crafters who need the handles need to worry about how rare their handle is, and whether it's worth it to just try and find a woodcrafter to make them some handles specifically for whatever they are trying to make...

It's a big mess. Especially given how much cross over there is in crafting anyway. You need this glue, and these nails, and that handle, and that blade, and this color of this kind of leather strips.