the 1979 film is not a post- or pre-apocalypse fiction. It's just dystopian.

Regardless of the Road Warrior prologue that places the events of this film inside the whole End Times scenario, this film was neither intended nor it should be seen as an apocalyptic fiction. But it is dystopian, particularly in the 1970s cinema sense. The dystopia of Mad Max (1979) is reflected in the following:

-de-funded public safety measures that leave the people defenseless. But interestingly enough, health services seem to be fine and somewhat advanced, in a futuristic sense. There seems to be a severed limbs bank, or maybe even a market, where these are claimed, bought or traded. This is implied when that guy comes to collect the thug's hand attached to the Max's station vagon's rear bumper. Even badly burnt victims like Goose are kept alive in intensive care.

-over-bureaucratisation of law enforcement. Radio chatter that warns officers to do by the book, and those lawyers that come with release papers for Johnny the Boy do not convey a sense of apocalypse unraveling, but a typical 1970s dystopia with a dash of movies such as Dirty Harry and Bullit, where tough policemen cannot do their work due to either an overly lenient justice system, or corruption among the higher-ups.

-overall decay of moral values, with upstanding family men like Max being regarded as the last remaining "heroes" in the world gone wrong. This again is more a feature of advanced decadent societies than failing, apocalyptic ones.

Also, there is a general availability of various public services and commercial activities (gas stations, repair shops, pet stores, grocery stores, restaurants, trucking, emergency services, car dealerships etc.). Max's house is almost an idyllic one. Also, there's a vacationing couple quarreling about infidelity early on, making them look like an ordinary middle class family. In the same famous scene, there's a camper trailer that gets smashed. So people work, go on a vacation, have babies. People affected by the Road Warrior prologue are going to say, "yeah, but the society was just starting to collapse." But, I don't buy that, and seeing the world of Mad Max 1979 in that light would just make it seem incoherent.

It's simply a dystopian "a few years from now" world. I don't know what the situation was in Australia during the late 1970s, but if you look at the 1970s cinema in general, there was a sense of unease about the failing public sector infrastructure and services, coupled with the corresponding agglomeration of powerful corporate entities (e.g. Rollerball). So, I think that Mad Max reflected those fears. It's an increasingly morally defunct, over-bureaucratized, over-privatized world. Sure, these things can be a precursor to apocalypse, but no, Mad Max is not a post- or pre-apocalyptic fiction.