Not common with build in dashcams, but Tesla do let you use their sensor cameras as dashcams ( though not stellar image quality dashcams )
Other provide aftermarket dashcams, which are often them putting their name on a cheap camera.
Denmark will be getting 3 natio wide 5G networks, meaning with my provider i will have access to 2 of them, and the country being pretty flat too, well i still dont have faith in being able to UL in real time.
I also have to admit that something like that is a waste of network bandwidth, but thats maybe a result of me being very much a anti streaming / vlogger person, for instance people streaming them self playing some game, well i just want to reach thru my monitor and strangle them.
I pretty much see next to no reason to be live with anything ( though i did just watch space X fly a rocket live, but it did not have to be like that, just the world infecting me with its stupid too )