KJVO-Types Don't Use 17th Century English

I have wondered why those who are adamant about retaining the language of the KJV ( at least in one of its forms ) do not use this kind of language normally . They insist that KJV-talk is perfectly understandable . Some even say it is less difficult English than that which the MV's use . But then , out of the other side of their mouths , some of them claim that the wording of the KJV is at such a dignified and intellectual level that only illiterate individuals cannot grasp the renderings .

I know that these folks try to incorporate KJV-speak in their audible prayers . ( Sometimes with a mangled Elizabethan in the process

Why aren't all the hymns they sing in an old-tyme style of English ? Why would they dare to sing words in a more contemporary vein ( like Fanny Crosby

These and related questions are awaiting answers .