How do you come to the conclusion that traditional OEMs are terrible at the sensors, software, and UX?
For example, Daimler/Mercedes is developing for years toward self driving cars. They had working prototypes in the 1970s with "electronics" based on analog designs that was working as good as a modern Tesla FSD, with the exception that it required lots of space. Mercedes/Daimler is the reason why we have cheap ultrasonic sensors in modern cars. They developed that in the 1990s together with then Temic. They had a working self-driving prototype during that time. All that lead to cheap sensors we use today daily for adaptive cruise control in every modern car by any OEM.
Mitsubishi had for sometime the best in class safety system with sensors able to detect pedestrians, like kids, and bicyclists.
MobilEye is now developing self-driving capabilities for years, and IRC first used by BMW for safety features in their models. Only later Tesla used the system in ways which were never consumer ready. That'S why they finally split.
The things is OEMs are conservative introducing features to consumer. Because nobody wants to risk its brand to devalue. Its not only that, if there are too many accidents that would mean that the insurance will have an extra premium, which would lead that consumers don't buy such cars.
So I was driven in car in the early 2000s with features that are rolled out just recently, like the level 3 by Mercedes on highways.
The things is, most just don't see how much things are going on under the hood. They just see the MMI/entertainment system. Yes, that was for long not as high value proposition.