I have more than 1 skills to earn a living - (cars is just fun/timepass for me),
you seem to have been drinking the Tesla Koolaid a lot too, I know first hand how bad the Tesla supply chain is, Any manufacturer in the past that had such bad parts support and such poor serviceability either packed up or remained a microscopic niche.
live example.
Tesla authorised body shop got a Model S P60D for rear bumper replace and paint, It took Tesla 27 days to send a bumper to the shop.
Same shop gets a 2016 Chevy Impala for same job, the bumper is delivered within 4 hours and installed, prepped and painted the same day. Vehicle delivered next day with complete parking sensor recalibration etc etc.
Both brands are local to USA,
btw - Tesla has a 1 spd gearbox, and a diff (technically specced as transaxle) - its bolted to the drive motor, Seen it touched it, diagnosed it, replaced it. BTDT.