It would be interesting to learn about predictions from back then about the future of society and relationships.
For example, would the people of 100 years ago have envisioned:
1. open homosexuality, and special rights for homosexuals in the law.
2. the women’s rights movement, so many women in the workplace doing any job a man would do.
3. the collapse of any social stigma against out of wedlock pregnancy and child rearing, which are also endorsed by our governmental policies of giving welfare to single mothers.
4. The open acceptance and legal access to pornography.
5. Various forms of legalized gambling across the country.
6. The decline in church attendance and decline in religious influence in the culture, and in people’s lives.
7. Acceptance of formerly stigmatized sexual behavior.
8. Entertainment media which pushes and normalizes what would have been unacceptable, bizarre, or immoral behaviors.
9. Decline of family ties, lack of social stigma against people, esp. women, who choose not to get married.
Just off the top of my head, I wonder about some of these things. And then wonder, based on some changes we’ve seen in society, do some of the changes I’ve noted help set the stage for even more changes? Will the structures of society which have changed in the last 100 years change into somethings we would not even envision today?
For example, no way people 100 years ago would have envisioned homosexual marriage. What might be accepted 100 years from now may not have even been conceived of today by any of us.
I do see Robert Heinlein in 1952 predicting for the year 2000 that "contraception and control of disease is revising relations between the sexes to an extent that will change our entire social and economic structure." Pretty easy to predict that, I guess. Cancer, the common cold, and tooth decay would also all be cured by now. Source
You may find things that were predicted on "slippery slope grounds" -- if this happens then sooner or later two guys will be able to get married -- but dismissed at the time as alarmist.