Sam Wilson, aka The Falcon, did not take the Super Soldier Serum because he believes it would fundamentally change his identity and take him away from representing the "everyman" ideal of Captain America, choosing instead to embody the role with his own natural abilities and leadership qualities, rather than relying on enhanced powers like Steve Rogers did.
The mantle of Captain America is not a physical one, or even mental, but a MORAL one. And Sam has that moral compass where it counts, where it needs to point,
Key points about Sam's decision:
- Maintaining his identity:
Sam sees taking the serum as a significant alteration to who he is, potentially losing the relatable aspect of being a normal person who steps up to become a hero.
- The spirit of Captain America:
He believes that the true essence of Captain America lies in the character and values, not just the physical enhancements, allowing him to connect with people on a deeper level without the serum.
- Actor's perspective:
Anthony Mackie, who plays Sam Wilson, has stated that he thinks it's important for Sam to not take the serum to maintain his unique role as Captain America.