Thinness does have some value for phones. For laptops, there's certainly a market for ultra portable machines but Apple seems to have forgotten that some of us use our computers for work and are willing to trade off thinness for practical usability.
I think the issue is that articulating that balance is hard - for example, the original thinner retina MBP lost some practical usability, but from a work standpoint for me, it was worth it for the increased portability.
same goes for smartphones, sadly the market has a tendency to align with 'stupid' goals and so no more production of non-thin devices. I'd be very happy with a thicker phone (larger battery, more shock resilience and even... some buttons)
