Research shows the archaisms like "thou", "thee", "ye" and endings in "...th", "....st" etc. WERE NOT COMMON in the day the King James Bible was done.
The first edition of the King James Bible came out in 1611. It is called the The Holy Bible 1611 Edition King James Version. In that edition there is a dedicatory to King James that is 2 1/2 pages that has NO archaic words, & also, there is a preface "The Translators To The Reader" that is 11 pages that has maybe 10 or less archaic words but mostly from quotes from the past.
Another example quoting Wikipedia for the word "thou": "In the 17th century, thou fell into disuse in the standard language." The King James writers found in the original Hebrew and the original Greek that there was a tone of (to quote Wikipedia) "religious solemnity". Any version of the Bible that does not use these type of words loses the BENEFIT of that religious tone that the originals were written in. For example, see the following link: http://en.wikipedia.org/wiki/Thou
And, there are many other examples.