It's all and well if all partners are well aware and participate in healthy practices -- but that is an ideal situation. Jealousy, favourtism -- or even children not knowing who their real parents are are some concerns that I put forth. Add to that the plethora of mutating STI/STDs that run rampant even in our (somewhat) advanced society... I think that wide spread polygamy is just a Pandora's Box waiting to be opened.
If pregnancy and disease were possible to be really controlled (to the point in not being a factor) polycamy _could_ work in a society built to tolerate it - something like the society in the novel "Brave New World".
No, it's not all up to chance. People are far more in control of their lives than you can imagine. I've lost count of how many people I've met who came from tiny country towns and flourished in the city better than I have - taking charge of their lives is more powerful than what the world will throw at you. Also, your perfect somebody is never found. They are forged by you, and you by them.
Why do you say such bizarre things? That you first say that love and companionship isn't necessary but then say that loneliness is a battle that can't be won?? It would probably be better to say that loneliness is a path that never ends, but that's about as useful as saying that humans are bipeds.
Buddha believed that humans suffer because of desires that cannot be fulfilled. If you remove these feelings of desire, goes with them your sense of deprivation and grief. The only way that you can 'cure' loneliness is to remove the human desire to have companionship. But as social creatures, we're psychologically and physically inclined to seek the company of others. A quick cure for loneliness is to have companionship. But if you are stuck being alone -- the battle is a bit more difficult. It comes with self control: to not fall into a spiral of feeling lonely and despairing because you are alone. This is what I mean - you can't just wake up one day and say, "I'll never feel alone again." It is quite possible to feel alone in a myriad of faces, and it certainly is more than possible to feel alienated from your spouse.
We are corporeal beings and we can only change so much of our lives. Coming to terms with reality is a great part of maturity.
You're free to agree or disagree with me. But I don't want to hijack this thread.