In the peri-marketing articles that appeared with the release of Fury Road, there was a lot of comparison to Westerns. This comparison is never explored, probably because it's wrong, and frustratingly so. Mad Max and Westerns both feature a lone warrior with a rough sense of justice fighting the good fight against desert savages. The difference is that in Westerns, the sheriff is fighting to protect civilization because he knows that things will eventually get better. In Mad Max he keeps fighting despite knowing that things will only get worse. In Westerns, good folk set up homesteads on the frontier knowing full well that there are savages around, but the settlers can be reasonably assured that the sheriff or the cavalry will gallop to their aid from the unassailable (if remote) centers of civilization back East. In Mad Max, there's no hope; the raids tomorrow will be worse than the ones today, and for damn sure there will never, ever be any cavalry to help you. (In fact, you should assume a lot of the savages used to be the cavalry.) Yet, despite this, Max does retain something we recognize as a sense of right and wrong, which appears increasingly absurd given the futility of resisting the overwhelming tide of barbarians and madness. And that's why he's interesting. The free will to choose right instead of wrong is the only thing left to him, and he chooses right. Mad Max is much more like Dr. Rieux in The Plague than he is like any frontier lawman.*
That leads to the second part. Mad Max movies revel in how much nastier the world keeps getting each day. Mad Max movies are apocalpyse porn. Through the four movies we watch as life gets progressively more nightmarish. We go from some punks robbing people in the first one, to an irradiated Darth Vader wasting water in front of dying old people and imprisoning women for their wombs and milk. Why this dystopia fetish? As always with any fictional narrative, we can break the answer into two kinds of influences: forces internal to the logic of the narrative (what happens in the story), and forces external to the medium (that is, economic forces in the real world where the story is a product). Internally, we get the filmmakers' message that oil-based society will crash badly, and that nuclear war would have grotesque consequences. Externally, over time these movies found themselves in a market with more and better action movies and had to sell tickets. Utopias offer few opportunities for violent conflict and therefore ticket sales. And frankly, there's also a very real pornographic aspect to making the world more and more hellish that emerges in post-apocalpytic fiction generally.
Absent from the movies after the first two is any kind of collapse-of-moral-authority warning that social conservatives love to illustrate in detail: that if we let the softies and criminals take over, well then the strong men are justified taking matters into their own hands to give the baddies a dose of their own medicine.** (Maybe all social order requires a threat of violence somewhere at the core of the system, and the very real but better-socialized psychopaths currently in charge get mad at the threat from outsider psychopaths, and ache to respond in line with their true natures.) In the first movie, Max is a cop, guarding the roads and avenging his family. Certainly by Thunderdome, there is no longer a clear source of legitimate moral authority (at least with armed, loyal adherents to enforce it) for Max to defend anymore. Was there ever a legitimate authority? Possibly the greatest cruelty of the world of Mad Max has been to take away even the past by exploding the comforting myths of history. And possibly, this bothers us because we've had the same thoughts.
*Deserts tend to figure in existential and/or exotic fiction for Europeans and people/cultures of European descent - even cultures that have deserts, like the U.S. and Australia - because to European eyes, the desert is bizarre, and open, and by its nature obviously threatens our continued survival and even our sense of our own significance in the scheme of the universe. Science fiction may rely a little too heavily on this trope, although granted, Dune would not have been the same in a boreal forest. Still, I can't help but wonder at the source of the different roles that deserts play in the psyche and literature of Australians and Americans. American deserts are a little more liveable, and they have mountains and therefore rivers and occasional green spots - versus Australian deserts, which have much nastier critters, and which look like Mars with a few tufts of grass, and are about as good at growing crops. Australia doesn't celebrate its desert-crossing pioneers to the same degree as America, because mostly what the Aussie explorers got was a clap on the back from their countrymen that they made it, after accurately reporting back "Yep, it sure sucks out there." Australia also doesn't celebrate its homesteaders, because to a first approximation it doesn't have any, and can't. Consequently, American deserts became places of optimism and adventure and conquest, and Australian deserts are places devoid of meaning and best avoided.
**Have you noticed the following pattern with Mel Gibson's characters and scripts? A moral man driven to darkness by his enemies, angst-ridden, often taking vengeance on those enemies in horrifying ways only slightly less insane or evil than them. Mad Max, Lethal Weapon, Apocalypto...and what was that Roman-Middle Eastern one?