In [this 15-minute video](http://vimeo.com/67418669), John Hess gives a terrific overview of the history of the screenplay format, and how changes in the film industry changed the way the words are arranged on the page.
I could quibble with a few things.
First, the modern screenplay has an obvious analogue in the stage play, and didn’t develop in a vacuum. Second, Hess gets a little proscriptive at the end of the video, and conflates screenwriting software with the format. (Which is part of why we made [Fountain](http://fountain.io), to untangle the writing from the formatting.)
But his overall point is worth making: the screenplay format *is* what it is, and it’s a fool’s errand to try something wildly different.