I believe the reason Apple hasn't implemented C/P is related to the way they co-opted the standard mouse gestures (click-drag & Double/Triple-click) and use them for navigation (scroll/flick & zoom), instead, on the iPhone.
This leaves them with no intuitive way to select content on the iPhone.
Some have suggested a modal solution where an iPhone gesture (say, press-hold) puts you in "content-select" mode, where you, then, use the loupe to select content.
While, not an ideal solution, it would prolly be OK for the iPhone.
But, here's the rub-- Apple plans/wants to introduce other MultiTouch devices (tablets, portables, desktops, etc.), presumably, with larger MT displays than the iPhone.
Say, you are using a 30" display as a light table to manipulate your photos and their titles and metadata. The iPhone implementation (touch-drag & double-tap) breaks down-- you (usually) want to select objects (or parts of objects), not the entire display.
I don't presume to know what the answer is, but I do think that touch-drag and double-tap gestures need to be consistently implemented across all MT devices.
I suspect, that Apple will need to redefine the iPhone gestures for scroll/flick and zoom to free-up touch-drag and double-tap (say using 2 fingers instead of 1?)
The best way to do this without inconveniencing the customer is to have a setting on the iPhone (current way or 2-finger way).
Then, give them a reason/incentive to change (be compatible with other MT devices).
Whew!
So, if Apple implements C/P on the iPhone, today, they must come up with some Jerry-rigged modal selection that would have to be re-implemented/unlearned later
or
Come up with the revised iPhone setting described above-- but, then they would need to explain why they are changing things...
...Apple can't do that without telegraphing their intentions for new MT devices.
What to do?
Let a few iPhone customers bitch and moan about no C/P... and ignore them (until they can do it right).
That's exactly what Apple s doing, IMO!