The humanoid bull story assumes cost falls all the way down — Musk targets $20K for Optimus. But Morgan Stanley calc'd that "de-China"-ing its supply chain jumps the BOM from ~$46K to ~$131K — nearly 3x, because the actuators, reducers, screws, and magnets that dominate cost are where China leads. The body maker's tradeoff: cheap (lean on China) or secure (swallow 3x BOM). A body can pick only one — which is why it's thinnest-margin.