Heh, you seem to have misread Eliot - he very much was using the common speech, in contrast to models like Tennyson, who were deliberately periphrastic. Eliot himself tried to establish himself as using a more common speech - I believe he phrased it as the language of conversation.
Periphrasis comes and goes with tastes - it was surely in fashion during Shakespeare's time, and the influence of John Lyly on his work - you can trace the development of his style too, from the pun crazy, rhetoric loving pentameters of Romeo and Juliet to the more loose highly enjambed verse rich with metaphor and imagery in The Winter's Tale.
The KVJ never was, and never will be spoken language - written and spoken English didn't really collide from my knowledge until later - the actual people's speak is generally different - take American fiction now, for instance - only drama is written in the vernacular - the literary diction is modeled after British trends, which too don't reflect the spoken language.
The Bible was meant to emulate the sort of archaic tones of the Old Testament in its translation - that's the reason for the language - it has nothing to do with spoken language, as, quite simply, literacy at that time was pitifully low anyway.





