iPhone owners could do all those things to increase their battery life, but the fact is that the standard these days are too high for users to adjust their phone use because apple didn't care enough for it.
They basically took two steps forward and then one step back.
People nowadays aren't that patient and expect a lot when they're paying hundreds of dollars for the phone.

I personally don't have a problem with checking my email less and dimming the brightness on my phone but i think apple could have done better.