Right but big robot arms do need to be reprogrammed. In short we traded higher throughput for less flexibility. Tooling and such is expensive and complicated. A sheet brake and a welder and a mill and lathe can produce a LOT of stuff without any expensive tooling.
This has always been the trade off. One of my first design jobs was working for Simco. They made boxes with fans and ionizer and you could design what ever you want as longs as it’s bent sheet metal. I’m trying to develop a small run manufacturing facility. Last step is a 9 month composite construction certification course in September. I think composites will provide freedom in the final form and flexible tooling.