This thread is simply not true. My iOS 7 device can easily last all day. OP doesn't know what he is doing.
THIS POST is simply not true, at least not completely. Battery life varies between device to device, depending on age, model, settings, use, etc. Some people will have good battery life and some will have bad.
What will people's excuse be after release?
Instead of "it's still in beta!!!!!"
Maybe it'll be "it's just been released!!!"
And then a few weeks later if people still complain the excuse will be "7.1 will fix everything!!!!"
It also varies based on the user and their circumstances. One day I may get decent battery life and the next it may suck because I'm spending my time in an area where the cellular coverage isn't optimal. So nobody can claim, "I get great battery life on my iPhone 5 so you must not know what you're doing".
In no way am I stating that battery life is the same across all phones. And of course there are environmental factors that can effect the battery life. Whether the phone is being used all day or the user is in a location of poor signal and the phone must work harder to maintain a connection can deplete the battery faster than average. These issues should be common knowledge for person who has access to the beta, e.g. a Developer.
The OP states that he is losing all his battery within a 1/3 of a day with all apps closed. It is not an issue with iOS7 but with OP's phone. It may need to be returned or OP doesn't know how to properly install the beta software.
Or the OP is sitting in an area of low signal (as you just explained in your reply to my statement saying the same....)