The Mad Max series gave a big boost to the genre of "post-apocalyptic" fiction. Foremost among them was The Road Warrior, which veered away from the Death Wish style social commentary of the first movie and dove straight into life after civilizational collapse.
I'll be honest: this is a pretty stupid movie. It has plot holes the size of semi trucks and all sorts of hand-waving to push things forward, but it has had a huge impact on the public imagination.
Which is funny, because the story makes no sense. For example, there is no reason the protagonists and Lord Humongous can't simple do some sort of barter trade. Even the most violent barbarian peoples - the Mongols, the Huns, the Vandals, the Goths - were wiling to trade when it was profitable.
Also: where are the firearms? No, I don't expect craft weapons, but they clearly have the metallurgy to soup up engines - machining barrels and bolts to make crude firearms is no great stretch. In fact, we know these things exist in places like the Khyber Pass - which is a pretty anarchic place.
All that aside, the movie's distinct look has become part of popular culture, which means that even though it's deeply silly, it can't be classified as anything other than a smashing success.
Truth be told, the whole point of the film is to do a bunch of violent car wrecks. That's what we really want to see and that's what we get.
There is also a lesson insofar as the people who work to overthrow the existing order often have no clear notion of what comes next. In that sense, the plague of ultraviolent punk rocker biker dudes serve as a cautionary tale for our present age.