Happiness is by its nature not a permanent state . I am not sure if this premise that you base your arguments on is reality.
Happiness is a feeling that is not measurable and needs to be always present. That is the default setting in nature. Human beings need to coexist with everything else in nature and be in alignment and happiness will be permanent.
Human beings as a species have imagination that is an added feature over all the features that other species have. Being independant to use his imagination for understanding reality is the objective of his existence. Education can help each human being direct his imagination to that purpose and help him achieve the same.
Now Human beings have to be aligned on three fronts.
Within themselves they need to align their thoughts,speech and action which are very tightly intertwined.Any misalignment in them will lead to weird behaviour and eb a source of pain to himself as well as other human beings.Education can help him to align these activities and slowly reach permanent alignment.
All behaviour that happens is because the person who does that has been educated to find it beneficial to him. It is incomplete education and the person can not be blamed for the same.Given proper education he will be able to see those actions in better light and correct his behavior.
People with major accidents who lost body parts have been found to be happy and adapt to the new reality.There are many research papers to prove that and I can google them and share in case you are not able to locate them.
The second front is aligning with other human beings and thirdly with nature.
Once the self is clear we can then discuss the other two fronts also.
I respect your thoughts and would love to help you get more clarity and would be grateful to you as you will help me validate if my thoughts are correct and on the right track.