Nobody's ever gotten enough people to buy either a phone with a better camera or a better camera add-on for a phone (unless you count a drone as the latter) to make it work. Samsung tried a couple of models with a 2/3" (?) sensor and a zoom lens, and nobody accepted the camera bump. Motorola (?) had at least one model with a 20 MP 1" sensor and a little bit of Hasselblad DNA, and (again), nobody wanted the bump. Nokia had some larger sensor and a pixel count above 40 MP (phone-sized pixels in a larger sensor), and, yet again, the camera bump killed it. Joe and Jane Consumer want ultra-thin phones, and that means they get microscopic sensors with 5 stops of dynamic range. DxO tried an accessory camera, and nobody bought it.
The only remaining hope is a version of something like SnapBridge that really works. Send images from camera to phone without physically connecting the two, with some sort of always-on connection...