When they designed the cameras, maximizing battery life was a major focus.
One of the ways they achieve that is how the camera uploads video after recording. WiFi is a power hog, so the video records on the camera and then in a quick burst it’s uploaded to the cloud.
Yes, there’s a live view, but even there they tried to enforce power savings; you can’t stream for more than like 20 seconds before the stream pauses and you have to tap to continue.
Don’t get me wrong, recording from the live view could be super useful, and many people want it (which is clear from above).
But doing so could potentially have a huge effect on battery life. And then some people would inevitably complain that their batteries don’t last long enough.