>>I just want to know what period of our History fits the category "better days behind us"?
>
>1776 up to about 1990.

Actually, drop the last ten years. I've seen statistics where the standard of living was (except for drawbacks like the Civil war and depression) steadily rising until late seventies, and there it stopped. Real wages lay flat or drop since then, the rich get richer, the poor get poorer, and the wages don't rise. That's where the overall progress ceased and turned into a different kind of progression.