Based on an experience with my own Mach-E I wrote this article to raise awareness of the impact a slow network has on updates. This is more than just EV's as ICE vehicles are catching up on software. https://www.linkedin.com/pulse/software-updates-your-car-its-network-stupid-dave-cronberger
I am no expert, but I think you make some invalid assumptions in your article. First, while there may be 150 million lines of code in the car, that does not mean that the entire operating file is being updated. A tiny fraction of that file is being swapped out. Similar to a windows update, which is done in the background, and the only time consumed is the actual exchanging of the file and rewriting of the executable files that need to be changed. The reboot of the system is the biggest time sink Second, I am not actually buying the amount of time you are allotting. I have a thumb drive that has 105 GB of used space that I can download or upload in a few hours. It might tell me it is going to take 8 hours, but it doesn't. Thumbdrive in the techs computer, thumbdrive into car, done. Tech does something else while the car[in the parking lot] updates 16 gig thumbdrives are practically free. A drawer full of those would keep thru put at the dealer going
Personal experience: Took my Mach-E to the dealer for an upgrade that could not be done over the air. The file download alone took over 6 hours. Then there was the install. My car was at the dealer for nearly 2 full days. True it depends on what kind of update is being done and how it is staged. On my other 2015 mustang an update to the APIM took 2 hours. So I think I am actually in the ball park. My bet is for many reasons thumb drives area non starter, however having software pre-staged could be a big help.