I think LLMs will be excellent glue of "find the right function/button and run/push it" but design without constraints and they just explode immediately
Asking AI to design real world objects doesn't work very well because all of its tests involve proxies and thus miss things that are glaringly obvious when the object is actually built.
Why do you say this? I have some experience of manufacturing processes and am not seeing where AI would be useful other than to drive the robots which we can already do quite well without AI (see all the dark/lights-out factories that already exist).
Where do you see it being useful? An example would be nice.
We already have sneaker designs and the equipment to manufacture them. Whatever it spits out is going to be, at best, a mediocre clone of something that already exists. What exactly is the point?