I would also say they probably will not do this.
The first reason, as basically everyone else here has stated, is that Face ID is likely going to be the new standard for Apple products going forward. The iPhone X was the first generation Apple product with the feature, but more products likely will adopt it going forward, and I believe Apple will continue to refine/improve the hardware and software around it.
Another, more practical reason, IMO, is that with all the technology in and surrounding the screen functions as they are now, would adding another layer of functionality even be doable? The biggest one that stands out to me is 3D Touch, which already demands sensors under the glass screen. If Apple were to try to implement some version of Touch ID beneath the screen, I can only imagine it would be a challenge, to say the least, to do so on top of the 3D Touch hardware in a way that's seamless and integrates both functions. It's like why try and do that when they have Face ID? And I don't see Apple moving away from 3D Touch anytime soon, given that its functionality is baked into so many core iOS functions.
The first reason, as basically everyone else here has stated, is that Face ID is likely going to be the new standard for Apple products going forward. The iPhone X was the first generation Apple product with the feature, but more products likely will adopt it going forward, and I believe Apple will continue to refine/improve the hardware and software around it.
Another, more practical reason, IMO, is that with all the technology in and surrounding the screen functions as they are now, would adding another layer of functionality even be doable? The biggest one that stands out to me is 3D Touch, which already demands sensors under the glass screen. If Apple were to try to implement some version of Touch ID beneath the screen, I can only imagine it would be a challenge, to say the least, to do so on top of the 3D Touch hardware in a way that's seamless and integrates both functions. It's like why try and do that when they have Face ID? And I don't see Apple moving away from 3D Touch anytime soon, given that its functionality is baked into so many core iOS functions.