Basically he's saying that if you want your new phone with 10x power requirements to have the same battery life then you'll need a battery with probably 10x the capacity - not 2-3x like they do now.
Some old Nokia vs Samsung Galaxy S3.
1.8-2.8" screen vs 4.7".
200mhz CPU vs 1.5Ghz
850mAh vs 2000mAh battery
Old OS vs New Hotness OS. (LOL)
I think everyone agrees with you already though, Phones being 7.7mm doesn't do me no good, i'd much rather them being 14mm (DOUBLE!) if that meant i could get a good 2-3 days usage from it. When you think of it too, 14mm is not even that thick, it's about the width of an average pinky finger.
So yeah, my phone now is 9.1mm (Nexus 4) and i saw some people bashing it saying it's so thick compared to the iPhone 5 (or even SGS3) because it's 1.7mm thicker!?
I'm like WTF is wrong with people, 1.7mm is so small that it's not even something i'd think of when comparing 2 devices. Weight surely but not that small of a difference in thickness.