My brother in law is a plant process engineer (six sigma/TPS) that worked at TMMTX as a contract job although not for the stamping tooling this story involves. But I guess they discussed it and he told me the story:
The consulting company that was hired to help advance the process of stamping tooling changeover speed. My memory of the story went something like this: about 15 years ago the consulting firm was asked to help speed up the stamping change over and they started by doing research on other factories and how fast the were able to do it. The fastest other factory they could find was a VW? factory in Germany that could do it in 4 hours or 6 hours or something on that order of time. Toyota was already doing it in 8 minutes and wanted to do it in 3 minutes. The team went back and said, "why do you want it to be faster, you're already the fastest in the world by a huge margin and it doesn't look like anyone is even trying to catch up? You're asking us to figure out a process to cut the time by more than half when you're already doing it so much faster than anyone else." And the answer was, "we don't really care what everyone else is doing unless they're doing it better than us so we can learn from them. Otherwise, we think it can be done faster and that's what we want to do. Can we make it happen?" And off they went to work on it.
I think this is what is so out of character for the long time between model updates and long delays on the BOF models. Toyota is known as being exceptionally nimble in new product development and going from concept to production faster than everyone else. The long delays are out of character. Lean manufacturing can also result in fragility. In a dis-integrating global economy the less vertical integration a company has the more exposed they are to the changes.