Beats me, but I’m not sure why this matters. Musk apparently feels that the best way to increase automation in Tesla’s factories (completely or not) is with humanoid as opposed to specialized robots.
You seem wedded to the status quo, specialized robots that do one thing. As I noted before, that’s how Toyota and GM make their gas powered cars, which works well as long as the technology doesn’t change significantly. But if it does, good luck.
But I think the world is changing with the key to economic success for most companies the capacity to rapidly adapt and take advantage of those changes. Tough to do if your manufacturing infrastructure is based on machines with limited abilities.