Ya, the '70s had a lot of good future shock sci-fi flicks... THX 1138, Logan's Run, Omega Man, A Boy and His Dog, up through the Mad Max movies (leading over to the car chase movie thread).
One in particular I remember as a kid was called 'The Stranger'...an astronaut lands on a parallel world earth...just like Earth, even has '73 Plymouth Furys...but not Earth