Matt Singer has an insightful piece on how Sylvester Stallone’s films have mirrored the actor’s career:
What Stallone’s done is basically without precedent. All of his former rivals for action film supremacy have faded away or moved on; all of his predecessors turned to moodier and more reflective work by the time they were his age. This is a situation that suits Stallone, since endurance was always the most important value of the “Rocky” movies. Rocky Balboa’s greatest strength as a boxer wasn’t his footwork or his punching power; on those fronts, he was mediocre fighter. What made Rocky extraordinary was his ability to take a punch and never go down. Though he has occasionally tried to distance himself from the character in his career (typically when he’s working on something other than blue-collar action films) it’s clear that Balboa is an extremely autobiographical character for Stallone. Rocky’s story is Stallone’s story: the dreams of an opportunity to prove your greatness, the struggle to remain hungry amidst the trappings of success and fame, the realization that you’ve lost your spark, the desire for one last chance.