Quite a few people, I'd say, given the number of post-apocalyptic science fiction films that came out in the 70s (A Boy and His Dog, No Blade of Grass, Zardoz, The Omega Man, Beneath the Planet of the Apes, etc). But it certainly popularized the idea. I haven't seen this in years but it is certainly notable for any number of reasons, and it certainly made Mel Gibson a star. I recently re-watched the first Mad Max film and had forgotten just how charmingly lo-fi it is. This thread may inspire me to see this one again too.