A simple concept if one allows it to be.
Dopamine isn’t happiness. I was a meth addict and dopamine is more like drive or excitement or motivation. Which we tend to confuse with happiness because of our consumer/workaholic culture.
Oxytocin requires connection. Dropping Molly alone vs with people for example is a very different experience. The later I’ve certainly found a lot of happiness through. And a ton of self compassion and compassion for others. Likewise oxytocin is produced when you bond with a child. Finding compassion and connection with my crying infant for example, I’m sure oxytocin played a part in.
Serotonin likewise isn’t happiness by itself. It is the rest and digest molecule which can certainly help a person find happiness, after all Samadhi is the beginning of the contemplative path. But finding rest is only a part of things. Self compassion is required to give yourself permission to rest.
I study neurochemistry. Mostly a layperson but I obviously have a lot of first hand knowledge of how these molecules affect people, as well as some college level education on it.
And I’ve been practicing and studying Buddhism off and on for eight years.
The molecular hypothesis for happiness is an interesting one. And while I have felt lots of euphoria on drugs, I’ve only found what I would call happiness or contentedness in relationship with other people or nature (which also requires compassion, even bugs value their lives.)
The three jewels are the Buddha, the Dharma, and the Sangha. Without the motivation (thank you dopamine) and the ability (thank you serotonin for keeping me calm) there can be no connection to the Sangha (thank you Oxytocin for the ability to connect and feel compassion).
So yes, the molecules you mentioned play important roles. But your comment is reductionist and misses what important role they play and how the contribute to the true happiness we find in community. No Sangha means no Dharma. And no compassion means neither Sangha or Dharma. And no Buddha, as he was the lord of compassion.
Take care and be well.