A while ago I was driving from San Francisco to Los Angeles and while desperately searching for something to listen to on the radio I briefly heard a moment of Christian Radio where the caller was quoting verse complete with all the antiquated language "Thou, thine, shalt, unto" and the incongruity of his voice and the language made me think of something. These are translations. That means there is no real reason to use the "Thou, thine, and unto's" In fact, there is a lot of overly complex language and sentence structure which could easily be rewritten to contemporary language and still be just as accurate a translation. But there is not a chance this will happen.
Why?
We like codes. We like secret handshakes and Nicknames. Couples invent terms of endearment. (If you're not sure what the translation of "term of endearment" is... it's the silly names that couples call eachother. Imagine six single people in a room and one couple and the man says to the woman "Ohhh, thank you pumpkin knuckle" while the single people think "Yeah, I oughta knuckle his pumpkin!")
Kids have clubs with codewords and things only the kdis in the club will know. Adults do the same thing. It makes us feel like we're a part of something. One word: Fraternity.
Humans have such an incredible drive to be part of a pack that we are willing to forego logic to make it so.
Tradition is the same thing - why is it done such a way? Because it's always done this way and doing it makes us feel that we are a part of history, just like have the secret key/code makes us feel we are a part of the present - and the current pack.
Often when I find things are illogical, I run it by the secret code word test.
I think I should invent a secret codeword that only my "fans" get to know!