Agreed, but what "feature" does a 1080p display provide over a 720p one? The smartphone/dumbphone comparison doesn't really work - there are no new features here.

For one, reading text is much more pleasant.

For me, slightly more pleasant text reading is not worth battery life. Reading text on 720p is absolutely fine.

First of all, the battery life improvement with 720p vs 1080p is negligeable. Screen size and brightness matters more.

Second, there is such thing as a 'good enough' battery. For most people, this has been achieved with the current crop of big screen, high res phones.

Not sure why you think people would accept lower resolution for an extra half hour of battery life...

What's the point in having more hours of battery life than your own number of waking hours? No one has ever adequately explained this to me.

Say I forget to charge my phone during 20% of the nights. A battery that lasts a single day will fail me very often compared to a two-day battery. Not to mention that unlike "dumb" phones, the iPhone won't turn itself on automatically to wake me up in the morning. Also, battery life is measured for "normal use". If you are draining your phone eg. by using it for directions in a friend's car without a charger, then it's suddenly more like 4 hours of battery life.