I am very curious what led that time in history to spread wealth so evenly. I don't know much about it, but for about 50 years technology was giving us such ama

I am very curious what led that time in history to spread wealth so evenly. I don't know much about it, but for about 50 years technology was giving us such amazing, shared increases in productivity and standard of living that people dreamed of a post-labor society. (like star trek). I met someone who's been with a company for nearly 30 years. When they started, everyone got 15 vacation and 12 personal leave days a year. It's unthinkable now. Why?