Earlier quoted context omitted.
How about a bigger battery? My primary criterion with each iPhone purchase is which has longest battery life.
Apple has decided that people want to buy razorthin phones and there is just not way to fit a large battery in there. I wish there were phones built like the old IBM thinkpads. Bulky, square, ugly but also indestructible and fully user servicable with replaceable batteries.
Not thin; light. Phone makers make phones lighter so that people can hold them up longer before their hands get tired. A battery is massy, however dense it is, whatever the shape. You can only add so much battery before your phone gets too heavy to comfortably hold. (Unlike, say, an external camera lens, which increases volume but not really mass.)
Thinness is just a side-effect of lightness, because the alternative—a “hollow” unevenly-dense phone—would be awkward and unbalanced in the hand. You make a phone lighter, keep the screen size the same, repack it to an even density to keep its center of gravity the same... oops, it’s thinner now.