With the fallout of Vietnam, the continuing threat of mutually assured destruction, and other socio-political issues spilling over from the 70s into the 80s a darker tone in comics was inevitable. But that is just the backdrop for comics. Comics had to adapt their content for the direct market. Their readership was aging, and so, they had to adapt the content to reflect their aging readers. Inevitably, the comics grew darker. They became more violent. They grew more socially and politically aware of the world and would comment and parody it. Because of the aging readership, comics had to grow and adapt. So not only did they become darker, they became more self-referential, commenting on comics history and past issues. Instead of broadening their audience, comics selected and reduced their audience, focusing on readers that they already had.