I think the analogy with mass production of automobiles is strained. There is a huge difference between making hundreds of something (fusion power plants) compared to making millions (autos). Even Tesla has yet to demonstrate a capability of making millions (of dollars, yes; of cars, not yet), but that's what is necessary for an automobile company to succeed long term. The point being, fusion (or fission) power plants will never see what we commonly think of as economies of scale. I was in a company that was making a tech product projected to sell in the hundreds of thousands a year, and we had a tough time finding a manufacturing partner in the Far East that would touch it. It was just not economical for them in so low volumes, the economies of scale weren't there. We talked to Swatch in Switzerland about some small machine parts and they laughed us out of the room. They said they would run their machines for one hour and produce our annual part requirement.