Anywhere else on the internet this would be a problem.
Here on MacRumors, NOPE, Apple can't possibly have buggy software
Seriously, facepalming reading replies in here
I disagree. I'm not here to defend any multibillion corporation. However, I do realize there is a difference in opinions on many things.
Usage creeping up (as you put it) can be due to many reasons. You give the perception that its Apple's fault.
Yet, every phone I've ever had, has had batter loss while not using it in stand by, had data sent to the carrier during the times of non-use, and yes sometimes even not work.
Nothing is perfect, to expect as much and then complain when its not does give off a "needy" image.
It is a phone, and it is a small hand held computer. While on, it will send and receive data, regardless if you're using it or not. This is most likely applications sending data with/without permission in the background (such as notifications, etc) or even your carrier sending data.
The iPhone itself is stupid, it will only do what its told to do. By you or the software.