Garcia is not an action movie per se. "Action film is a film genre in which the protagonist or protagonists are thrust into a series of challenges that typically include violence, extended fighting, physical feats, and frantic chases." The latter three characteristics are absent, and the violence is brief and episodic. Oates, who by the way is incredibly good in his part, is not thrust into anything, not exactly. He assumes his quest after being exposed to a situation of opportunity and having a desire to lift himself out of a run of places he has no desire to return to. His means he hopes to be more money. He's clear about that. It turns out he will commit to Elita too, a conflicting discovery, but he believes that romance without finance will fail.
Unlike an action movie and fundamentally not an action movie, Garcia spends most of its screen time building up character through its defining human interactions, which include El Jefe and daughter Teresa, Sappensly and Quill, Bennie-Elita, Bennie-Elita-Garcia. Garcia is far more interested in developing its themes via its characters than in anything else. There is plenty of action, but it flows naturally from the nature of the pot-of-gold at the end of the rainbow. Little does Bennie understand the price that will be paid for it. When he does, his code of honor cuts in and leads him to actions that he himself didn't anticipate.
This movie helps to define what a 70s noir is, which is something that you know when you see it, but requires understanding in order to communicate its qualities. The 70s noir is a bridge between traditional noir, maintaining certain of its character, but opening the way toward the more self-conscious neo-noirs that enter in the 80s and 90s.
The settings are fantastic. There are now quite a few neo-noirs set in either the southwest or Mexico, transcending the earlier defining technique of shadowed cinematography. The issue is not a technique like chiaroscuro per se but how that technique contributes to the noir character of the film. With Garcia, one could write an essay on how numerous details of costume, character, props (including automobiles), dirt, guns, guitars, nudity, are conveying and supporting the story.
Garcia has a directness we see in the 70s noirs and also the heavy irony of 70s films. There's a degree of black humor there too, also in 70s noirs, as when Bennie starts talking with Garcia's head and gives it a shower. That humor is there right from the outset when Bennie confronts Sappensly and Quill at the piano. Walter Matthau did some 70s noirs (Charlie Varrick, The Laughing Policeman, The Taking of Pelham 1-2-3), being an actor who conveyed comic and ironic character. His earlier supporting roles in the 60s as in Fail-Safe and Mirage, were building up to a fuller presence of such characters. Robert Duvall manages to do the same mixture of ironic humor and seriousness in several of his 70s noirs, like "The Outfit" and even "Badge 373". Hackman did this in "The French Connection". These protagonists all are able to see their situations and those of others, often frustrating and beyond their control, and treat them with a degree of humor.
"The Three Burials of Melquiades Estrada" (2005) is another neo-noir in the Garcia vein, and so is one set in New Mexico, "In the Valley of Elah" (2007). There are others.
Peckinpah went all the way with his noir hero, so to speak, giving us a noir ending in terms of life and death of the hero. By typical valuations, Bennie lost everything, and brought it upon himself by not playing it safe but also because he did discover something he had denied, that he really did honor the dead. He earlier tells Elita about all the crap involved in burials, since the person is dead and that's that. Yet his actions eventually belie these statements. What makes him tick and stop ticking is something inside himself.
Bennie finds love, honor and respecting the "presence" of the dead are values more important than money and life itself, although he's not about to abandon money.