Kal-El's ship crashes on earth a little sooner. He's found by early men who eventually discover his abilities and worship him as a living god. His offspring inherit weakened of fragmented versions of his powers and though interbreeding they become a different, dominant species. Societies are built with the cult of the Super Man as their backbone. His empire eventually expands and conquers the whole world.
Thousands of years later the divide between men and Supermen still exists. Kal-el survives in suspended animation, and his direct descendents control the world. Through resesrch and cruel experiments they try to find a way to become complete krypronians like Kal.
Suddenly, Kara's ship finds its way to earh.