Precursor crafting was never meant to be a cheap/nearly free way to get a precursor. It's meant to be a way that a.) doesn't rely on random chance, and b.) gains a great deal more immersion/the feel of being on a journey than just tossing weapons at Zommoros and hoping for the best. Except all the legendaries past Chuka and Champawat. I'm not sure what went on there.