Fiction is one of the oldest ways that people use to transmit real ideas to others. It's often a powerful way to transmit empathy or morals, in particular. This goes back as far as the Epic of Gilgamesh which thematically explored the concept of death and legacy, and before then, to oral stories.
In good stories, the hero often wins not just because they are stronger/better/faster, but because thematically they should win. Some virtue in them or some flaw in the villain, or both, helps determine the outcome. And if the hero doesn't win, then perhaps the story is about internal corruption, or a statement of negativity about the world, which in itself is a theme.
In this sense, the hero and villain conflict not just physically, but thematically. Their conflict represents competing themes, in addition to also just being entertaining for its own sake which is why we want to consume it in the first place.
A somewhat negative example is that more than half of the Mission Impossible movies have pretty forgettable villains. As a result, they're solid popcorn flicks due to the spectacles, but people will rarely list a Mission Impossible movie in their top three action movies. Answering "why did Ethan Hunt (Tom Cruise) win?" at the end of each movie often comes down to "because he's the best" or, when being generous "because he had such determination and courage to see it through... again".
The villain played by Hoffman in Mission Impossible 3 was one of the better ones, but that was more about his performance, and I guess he thematically represented dark nihilism. And Henry Cavil as a villain was mainly for the cool factor, again more based on the actor than the character.
Something like Dark Knight tends to stick with people more because the conflict between Batman and the Joker is presented thematically. Batman doesn't just win because he's stronger; he wins because Joker's nihilistic theory about humanity is presented as being wrong; the idea that everyone is secretly like him when pushed gets disproven. His theme gets defeated.
Another random positive example is Samurai Champloo, which is hard to believe two decades old now. In that show, Jin was a ronin (lord-less samurai) who believed there were no longer any lords worth serving. The final villain, Kariya, was the best swordsman in Japan and was the shogun's enforcer, sent to kill a girl Jin was begrudgingly protecting. They fought, and Jin asked Kariya why a man as skilled as him would serve a lame shogun. Kariya said that like Jin, he didn't view anyone as worth serving, said the days of the samurai are coming to an end, and that he serves himself while appearing to serve the shogun. He just likes a good fight, and this job gives him the best. He defeats Jin and moves toward the girl. But Jin gets back up, injured, to try one more time. Kariya asks why throw his life away like that. They fight, and Jin uses a sacrificial technique wherein he purposely makes an opening on himself, Kariya stabs him, not realizing that it was intentional, and Jin uses that to create a simultaneous opening on Kariya to get an even more devastating surprise strike against him. Jin collapses but ultimately lives, and Kariya dies. The thematic reason Jin wins is because, in befriending and saving that girl, he found a duty that he viewed as above his own selfish interest, and was willing to combine his skill with that sort of sacrificial move, which was his only way to defeat a superior opponent. The superior opponent, having nothing worth fighting for, could neither use such a technique nor would he expect that sort of technique to be used against him by someone with Jin's history.
The best action stories, in my view, are ones that leave me thinking afterward. A memorable character arc, either heroic or tragic or both. They compare and test themes against each other, in addition to just throwing fictional characters and their fictional abilities at each other.
What are some of your favorite pieces of fiction that explore or test themes?
