I am not sure with this one, I have always thought happiness was something extremely difficult to accurately be measured.
It also depends on how is the culture, because in differents cultures the question can be interpreted differently.
For example, years ago I remember reading that my country Venezuela was the happiest country in the world, and that sounded totally absurd to me, it wasn’t true at all.
I believe this era right now is the happiest of our history, we have less poverty, a better level of live, better science and technology that improves our lives. I really think our world is getting better, and that tomorrow will be better than today in the grand scheme of things.
Happiness is difficult to measure, but I believe that a large portion of it is what I wrote on this post.
Maybe if the AI's of the future don't go all "Terminator" on us we can have nearly everything we desire. Only that 'Hedonistic Adaptation' tends to come along and establish our new baseline emotional amount. Once something becomes our norm, we have the tendency to seek more.
So future advancements won't really help make people more happy. That is my belief.