The Last Man on Earth is a 1964 post-apocalyptic science fiction horror film based on the 1954 novel I Am Legend by Richard Matheson. The film was produced by Robert L. Lippert and directed by Ubaldo Ragona and Sidney Salkow, and stars Vincent Price and Franca Bettoia.
I knew I'd recognized that Will Smith movie as an old story, I just couldn't place it! Thanks for the reminder.
Yea, Omega Man is a bad 70's-soaked remake, unfortunately.
70's dystopian stuff was typically overly dramatic/melodramatic, and tried to bludgeon you with "look how bad this is", instead of letting it come to you in it's own time/subtle way.
As much as I criticise cinema today, that's one area where a lot has improved (the melodramatic stuff is usually pretty obvious and more avoidable today).