In the mid-70s!
Instead of being released as a book series throughout the 90s and Noughties, the Dark Tower saga is released as a movie series starting the mid-70s. This allows the one truly deserving of the role of the Last Gunslinger to rise to the top.
That's right, Clint Eastwood as Roland Deschain.
Just for fun, we'll cast Harrison Ford as Eddie Dean, Roland's wisecracking tet-mate.
Who else would be cast in this series?