Pretty good list that one! I liked that a film like Woody Allen´s Sleeper is included. Last Man on Earth should be there, but as it´s the same story as The Omega Man i guess it excusable. What about Stalker? One of my favorite films and rather dystopian, but maybe in a different way, desolate and mysterious. If collapsed societies count, films like Virus, Dawn/Day of the Dead etc could be others. My favorite "nuclear war and it´s aftermath" film is The Day After, sober and effective.
Got to mention the Polish 80s classic Seksmisja as well!
Oh, those trashy Italian flicks are all fun, Atlantis Interceptors is my favorite of those.