"Monogamy: Here Today, Gone Tomorrow"
For the September-October 2005 issue of Foreign Policy about as serious an establishment journal as you can find the editors asked various figures, "What ideas, values, or institutions that we take for granted may no longer be with us in 35 years?"
Jacques Attali, a Foreign Policy contributing editor and president of a microfinance organization in France, answered "monogamy." Though he doesn't use the word polyamory, it's exactly what he means:
Two hundred years ago, few people foresaw legalized divorce or open homosexuality let alone gay marriage. Abstract art and jazz were unimaginable. Aesthetics, morals, and family relationships, it seems, are the bane of the futurologist. We constantly speculate about the future balance of power, looming conflicts, and emerging technologies. Yet somehow, we imagine that morals and aesthetics are immutable. So we forget to ask how conceptions of good and evil, acceptable and unacceptable, beauty and ugliness will change. And they will.
Monogamy, which is really no more than a useful social convention, will not survive. It has rarely been honored in practice; soon, it will vanish even as an ideal. I do not believe that society will return to polygamy. Instead, we will move toward a radically new conception of sentimental and love relationships. Nothing forbids a person from being in love with a few people at the same time. Society rejects this possibility today primarily for economic reasons to maintain an orderly transmission of property and because monogamy protects women against male excesses.
But these rationales are dissolving in the face of powerful new trends.... Just as most societies now accept successive love relationships, soon we will acknowledge the legality and acceptability of simultaneous love. For men and women, it will be possible to have partnerships with various people, who will, in turn, have various partners themselves. At long last, we will recognize that it is human to love different people at the same time.
Read the whole article.
Frankly I think this essay is over the top, at least for as soon as the year 2040. My own guess is that 80+ percent of people will always choose monogamy (at least in some relaxed form) if only because it's simpler. But it's certainly noteworthy that such a prediction gets aired in such a prestigious journal.