I’ve actually thought about that very idea in detail. If the metaphors were all you learned, they would essentially just be words in your language. The problem is that the metaphors are so compact they lose too much detail to be really useful. A phrase like “Darmok and Jalad at Tanagra” could convey the emotional content of a situation, the irony, the moral of the story,. or whatever, but it lacks details about the situation it applies to right now. Did the Tenagra situation today happen while people were having a fight or shopping for shoes? The language would devolve to saying a momentous event happened, a comical misunderstanding occurred, I had a heart-wrenching disappointment… it would be like everybody talking by holding up cards with memes on them - a world I wouldn’t even consider living in LOL.