We as society shouldn't focus so much on being „happy“. Happiness by itself is not worthwhile. What are you going to tell on your deathbed and how will your relatives remember you? Oh, he never did anything, but he seemed happy all the time!
I wonder about optimizing your life around your deathbed, obituary, or your contribution to society…if it makes you happy I guess;)
Being happy, possible with substances involved, is not exactly inspiring to people around. And, usually, people try to keep away other people from such... inspiration.
Of course, you can be „simply happy“ and a productive member of a community. But usually happiness comes as a byproduct then. And there're lots of other emotions aside from „being happy“.
Maybe it's worth to optimise around reducing misery around or being a net-positive on society where the life satisfaction will eventually come. But happiness may be out of reach due to stuff you can't unknow.
Long term happiness is an art these days, being too smart is definitely not a prerequisite (more like the opposite of it). Also, I think we lack proper definition for it so people take it as some sort of nirvana levitating a meter above the ground type.
For me personally, living life that I will judge positively and without regrets on the proverbial death bed is form of long term happiness.