alt Hacker NewsThe point is a Homer or Twain, etc, were original authors of works and Eastwood was not an author of any of those works. If an unknown actor portrayed the lead in a Huckleberry Finn film, that would not elevate that actor to the level of a Mark Twain as an author.
As an author no.
But as a director, they could be elevated to the status of creator, and perhaps directing is the truer American art form rather than ...epic poetry or the novel. Which speaks to the core of the question at a different level.
Besides, Homer didn't write his own plots either, he adapted original screenplays, so to speak!