Trust me--on something 5mm thick, there is no optical zoom! Nor, on something 3mm thick, either! We even know that regular pens and pencils don't contain an optical zoom lens. Trust me on that, too!
Sorry, couldn't help myself! Remember, the point was that Apple's fixation on thinness is a problem. Set your imagination free! We're not talking about the 7mm thickness of the iPhone 6 and 6+.
However, on an iPhone 10mm thick, there certainly could be an optical zoom. And before you say that's too thick for users, keep in mind that people's iPhones in cases are often much thicker
even that that! My iPhone 4, for example, with its Otter silicone case is 15mm thick and fits in my front shirt pocket easily and comfortably! Such "thick" devices fit readily into purses, suit coat pockets, and backpacks.
Furthermore, there are even digicams on the market now with 3x optical zoom and image stabilization in which the lens doesn't protrude *at all* from the camera body! Amazing, but true.
No doubt you'll be tempted to counter
this with another non sequitur-- such as: "Oh, a 15mm iPhone would never sell. Trust me on that!" That could well be true-- although whether such a product would
sell or not is quite different from whether such a device is on one's wish list or could be made.
Plus, I suspect that an iPhone that would last a week on a battery charge, include a 2-3x optical zoom camera with image stabilization, greater RAM, and have a built-in smart case, would find a large market!