*Great* post overal chickensevil, and thanks for writing it up. I didn't know Panasonic was struggling that bad pre-Tesla, and I think you summarized the potential cost savings of the Gigafactory spendidly. However, I have one quibble with this part:
Elon has been quoted many times saying that the Model S was engineered from the ground up, and only 2% of it comes from the "parts bin" (best example being the Mercedes stalks and window switches). However, there are also many suppliers they did outsource to. I have personally visited the factory where the headliners are made/assembled (Nashville, IL), and the factory that produces steering knuckles and other suspension components (Mattoon, IL). Also I found
a couple good articles with infographics detailing some of their other suppliers. Granted, they're old, so with the pace at which Tesla moves, they could be out of date.
That said, I do think they do more in-house than most other auto manufacturers, and that's part of their advantage when it comes to gross margin. The other part is just having a car with demand that exceeds supply.
I think in particular your example of the computer hardware/software is key, because other automakers (tend to? or universally?) outsource production of those, which results in costlier systems and probably longer lead times. That's one area that has sparked a bit of a reaction from the industry; I believe a couple other manufacturers have recently set up software development offices in the Silicon Valley area.