Which you could also do by simply making the device a little thicker and have a battery run the entire width of the device. Point is past a certain point, thinness becomes more of a drawback than a benefit, especially given the trade-offs involved.
Given the option between thicker w/ a bit more battery life or thinner and lighter, consumers are choosing thinner and lighter.
> ...consumers are choosing thinner and lighter.
A) I'm guessing actually lighter more than thinner.
B) Are consumers really clamouring all that intensely for "Thinner! Thinner!", or is that a) because that's all that's offered, and b) the relentless hype from manufacturers -- above all, bendy phone maker Apple -- amplified by rarely-critical media?