Need author and title. The novella concerns a 3 man trade mission to a planet inhabited by a hunter gatherer race. Members of the mission try to interest the natives in technology to no avail. One member of the mission lives with the natives and discovers that they have surpassed technology to live in concert with nature. In the end one of the older natives voluntarily dies to make room for the newcomer in the tribe
Thought I found it, but I was wrong. Thought it was Chad Oliver's "Rite of Passage"
"Chad Oliver’s short story“Rite of Passage”(1954) focuses on the concept of cultural configuration. Three survivors of the crew of an interplanetary exploration expedition, one of them the official anthropologist, land on a planet of another solar system. They are welcomed by the inhabitants, whose culture is apparently primitive and pastoral. After a brief sojourn among the Nern, during which the anthropologist is taught the language by the village shaman, the other crew members are eager to introduce the basic elements of technology. The anthropologist, however, deduces correctly that the Nern have eschewed technology by deliberate option, by“editing”their culture“down to essentials,”i.e., the goal of“survival with maximum integration, cohesiveness of function, individual fulfillment, constant challenge, and peace”.
But it was not. It was also by Chad Oliver and was called "The Marginal Man" and was published in an Avon Original paperback called 3 to the Highest Power. Here is a review of the story from MPorcius Fiction Log:
Anthropoligist Arthur Canady is a member of a two-man team that travels to planets where primitive people live. Such teams give the natives sewing machines, rifles and steam engines to jumpstart their economies, fostering their development into suitable trading partners for the Earth. This story tells how Canady (veteran of many such missions) and his partner land among people who are just like the Plains Indians whom Oliver studied in real life, nomads who live in teepees and follow herds of large herbivores that they hunt with bows and arrows. These natives are unlike any other Canady has met before--they have absolutely no interest in making their lives easier with Terran technology. Soon he figures out why: these people never get sick and never die, so they have all the time in the world to sew by hand and hunt with bows. The secret to their incredible health and longevity: they rigidly control their population and are thus in perfect harmony with the ecosystem. The tribe has a set number of members, and a woman in the tribe will get pregnant only after another member commits suicide. There is also a ritual that appeases some gods or aliens or something.
Canady decides he wants to live forever among these Stone Age types and so he goes through the ritual, fasting on top of a mountain where he meets his spirit animal and blah blah blah and then the tribe welcomes him with open arms.
Oliver seems to have a thing about rejecting the technological life in favor of a return to nature.