Sensor driver ICs operate in different modes for still and video, so probably developer culture between different trains of cameras diverged due to that, earlier in the technology.

Cameras are also still a bag of trickster type computer, lots of ASICs talking. “Main CPU” is probably still a thing. So disturbing the path from light to FAT file entry may or may not open some can of worms.

Lastly I can’t imagine a team of Linux hackers in a large Japanese corporate writing UVC gadget driver for company platform... entertainment value and frictionless operation are very neglected/disincentivized part of engineering in the country.

Maybe the second point is the most relevant. They’re not designed to encode and export video to PC and that itself is a challenge.