Tesla's system is based on Linux which is based on Unix which has been around for over 40 years. It powers the majority of the Internet, android devices, banking systems, computer research, etc.
It's not going anywhere anytime soon.
Trivia - most cars use discrete operating systems custom engineered for that specific car. It's not open source.
It's not that, it has to do with the computer mindset. I tried to get a $2500 Dell Computer serviced yesterday that was manufactured in May 2013. No love. They would not look at it, and they have all the digital tools to troubleshoot it. They will not sell parts.
Let's say your 2013 Walkaknobbie SUV has a locked ECM. The VIN and security code is locked in it. The ECM fails (it is a computer).
You will be able to buy a ECM from the OEM, original supplier, or a junkyard. But the first thing you need to do is to either bench flash it, or install it to flash (depending on the car). If Walkaknobbie will not provide you with the flashing tool and the correct OS and table file, you are screwed. An ECM in a locked system only works on the car it was sold with. It's to stop theft. You can't just take an ECM from another car to defeat the security.