And all Nokia had to do was make the phone twice a thick to accomplish that
The trick is that the pure view camera sensor is 5x the size of the iPhone 5s. This means that the sensor has pixels about the same size as the iPhones.
Incorporating this would require a massive compromise to the rest of the phone.
For better or worse, there is no way that Apple will allow a camera to increase the size of the phone by that much to accommodate a similar solution.
Yeah, I said something similar a couple posts later..
Though if you really want my opinion, I don't know why everyone is trying to make this into yet another quality vs. mediocre argument. For its size, the 5S takes incredibly good pictures. It's not a bad camera at all. The Nokia does takes better shots, but, like you said, it has to sacrifice a little bit of thin and sleek to get there.
Whichever you like better all depends on where your priorities lie. If I wanted a good, thin phone with a solid camera, I'd get the iPhone. If I wanted a good phone with a great camera, and didn't mind the bit of extra size, I'd go with the Nokia.