Lens distance and space for optics are physical constraints. Engineering can go so far, but you canna break the laws of physics!
"Physics" and "physical" have very different meanings. No laws of physics are being broken by fitting things in tight physical constraints! That's just engineering.
No they don't ... an iPhone camera fits ABOVE the screen.
Fair; I didn't realize that. In either case, I hope you wouldn't dispute that having a phone even twice as thick as today's skinniest phones:
- Wouldn't make it impractical
- Would allow a camera array
The skinny phones already have issues with bending in a back pocket. There's starting to be pressure to make them thicker.
Because you're still not going to fit a large range zoom to a smart phone.
Depends on what you mean by large. 10 phone sensors give you the same surface area as a dSLR sensor. With fast lenses. A Phone with 25 sensors, as I proposed, would be able to have 10 wide angle, 10 normal-to-long, and 5 moderate telephoto (perhaps with slightly smaller sensors for the telephoto).
That plus crops is quite competitive with a dSLR. It won't match a Sigma 200-500mm f/2.8, mind you, but it will beat a dSLR+kit lens for wide angle, for portrait, and compete with a dSLR with an inexpensive telephoto lens (which tend to be in the f/4-f/8 range).
The kind of people who had small compact cameras and were happy in the days of film.
They do very well for me too, in good lighting conditions. My phone takes more photos than my LX100 or my full frame, actually, since a lot of it is outdoors in daylight without too much action. I picked a phone with what was at the time in the top 3-4 phone cameras on the market for that reason. My big-uns come out either for low light, fast action, or fun.
But (and this is my opinion) they will never be a substitute for the versatility of a full SLR system.
It will be... different. The thing about camera arrays is they also provide lightfield information, which gives many types of versatility dSLRs don't have. Lytro dipped their toes in, but didn't really do a great job with it.