We would both use this as an example - you think it is because people changed their views, I think it is because a big group of people bitterly opposed to this died off, opening the door to change.
I think we'll have to agree to disagree. FWIW, I hope you're correct. I'd love to see society avoid repeating mistakes, learning from alternative viewpoints and expanding what they consider. Sadly, the one concrete case I can have of changing viewpoints is my own: In my twenties I felt as you do. In the decades since I've seen people embrace willful ignorance and proudly stand by hypocrisy so long as they didn't have to accept anything that was outside of their "normal". I retain the hope, but I've lost the expectation.
Here's to the hope that my conclusions are wrong.