One of the main reasons I shoot with an actual camera body is exactly because it has a camera body. The ergonomics of shooting with a phone are terrible.
Obviously phones will never fit in your hand like that, so both will continue to exist because they serve different purposes. I am glad that phone sensors are getting bigger since when you don't have your camera on you they do a fine job (when you avoid the in-cam processing by shooting raw)
indeed you should use your hips instead of head/shoulders to weight the board, but it doesn't actually move more weight to the back (think about it, to go forward, the board needs to feel more weight on the front, for which it compensates by accelerating = increase speed + levels the board)
the weight distribution doesn't change, but your body had much more control over the distribution.
Obviously phones will never fit in your hand like that, so both will continue to exist because they serve different purposes. I am glad that phone sensors are getting bigger since when you don't have your camera on you they do a fine job (when you avoid the in-cam processing by shooting raw)