They could just build one phone with fingerprint sensor on both sides and allow on app chose which side works as unlock button and which one as volume button. I

They could just build one phone with fingerprint sensor on both sides and allow on app chose which side works as unlock button and which one as volume button. I doubt those fingerprint buttons are very expensive. Esthetically would even would look better and more symmetric with 2 buttons on each side - 2 as volume button on one side, one as unlock button, another one custom shortcut, e.g. Open camera