Looking at the Change of Character in Action Heros

Bruce Willis, Robert DeNiro, Sylvester Stallone. These, and many others, used to be stoic and emotionless tough guys in their youths, but now that they've aged they all seem to be the lovable and grumpy grandfather figures. What happened? Is this a good thing or a bad thing?

This article would analyze the change in the tough guy, action hero tropes of these actors glory days, and how they've changed to fit their age.