I learned, to my wonder, that there is an enormous difference in time between a comma, a semicolon and a period, for example. Edward Albee Even with all the years Film has been influencing this business . . . Playwrights tell stories verbally.
Screenwriters tell stories visually.
Visual storytelling in films places much less reliance on Voice than the verbal process of plays. That's not surprising. And it's not surprising that lots of Playwrights can write well for Film , while Screenwriters are hardly ever able to return the favor. You can lay this off to money. But the fact is, most Screenwriters don't have the Voice for theatre.