I mean ‘could do’ is subjective. The ROI that apple receives on R&D is substantial, so on that basis, include a portable projector in phones such that I can replace my tv with my phone - not being able to use my phone while watching tv wouldn’t be nice, so add anti-shake gyroscopes such that as long as my phone is pointing in vaguely the correct direction, the projection stays stable.
Possible with current tech? Hell no. But within the realms of reality for handhelds to do this in the next 15 years? I think so. Probably less valuable over health and other potential device functions, I don’t think about these things and so I wouldn’t know.
Thus, we are not at a point where portable computers should be considered ‘mature’ from an innovation standpoint, even if current innovation is slow.
Edit: and currently, that looks to be you and the entire iPhone engineering team