- Most countries gave woman suffrage in 1910 - 1950
- Slavery was abolised in most countries between 1800 - 1900, apartheid was abolished later but way before 1975 in any developed country.
- Wife beating was illegal in most states by 1870.
- Spanking children is legal in many countries, but is probably on the way out, and not a big thing for conservatives.
- Poor people are getting less welfare now than before. It was much easier to get welfare back in the 80s in most countries
- Most of the bans of capital punishment in developed countries happened in the 70s or before, many of the countries hadn't done capital punishment for a long time. US nearly banned capital punishment in the 70s.
But fact is, since 1975 we have becoming much more economically conservative. If liberals are always right in the end, and conservatives are just there to pace liberals. Why have we been going the opposite way economically since 1975? Also, all of your examples happened before 1980 and very few people are against them.
On the social side liberals are losing as well. Think about immigration, death penalty in the US, school system, police, etc. You think this is just a lag on the curve? A lag that lasts 30 years? Come on!