I get the mobility thing and I am sure it works for a lot of people. I travel a lot and years ago bought a
Yamaha QY10 thinking it would let me work on ideas on the move, in reality it was a lot of fun but found more utility in a pen and pad of manuscript paper. the QY10 died long ago, when I start to think about getting a tablet to use on the move I remember my experience with my QY10 and keep the cash for something else. And the QY10 had a big advantage (IMHO of course, I know "youngsters" can work touch efficiently) - Tactile buttons, not a touch screen.
I can see how electronic miniaturization and improvements in processor technology and memory will mean at some stage in the future a mobile device will have the power to do what can be done on a PC today, but it will still need a docking station and external keyboard and screen for ergonomic use when not mobile.
Cameras in phones are another issue. The lens is the most important item in determining the quality and you are not going to be able to have a high quality lens in a phone due to size limitations. Samsung makes/made a compact camera that is also a phone to try to overcome these limitations. Megapixels are only a small part of the story, the size of the sensor is more important, and by definition camera phones will only have a small sensor. Sensor technology will improve, which means the big sensors will get better as well as the small ones and the gap will not be closed. If you want snapshots for family memories, selfies to post on Twitface, or capture an unexpected event the convenience of a camera in a phone is obvious, but for landscapes and portraits colour me very sceptical.