I think about this all the time. When you are lacking emotional intimacy you will be prone to want to find it, hence more relationships, or an open relationship if you are already in one and don't feel like it's meeting your needs. I think the #1 problem with polyamory or whatever you want to call it is that when you are really emotionally intimate with someone you are very prone to being jealous and wouldn't want an open relationship. But yeah, if you aren't that close to the person, and you're not made jealous by them screwing other people, than what you say could work. I personally know people who live that lifestyle and say it works for them. Most people I think are ultimately seeking that emotional closeness, and so anything short seems like a failure.

I wish they could put actual odds on finding love etc, like you say, I've wondered those odds myself as well. Would you risk an 80% chance of failure on a 20% chance of ever being truly satisfied? Could you ever really calculate and compare those odds?