>But I'd imagine people would have to settle for a lot less than their ideal partner...

Well I grew up in a rural area, a town with fewer people than my intro biology class at undergrad. I've also lived in cities, including as a kid prior to moving to the rural community that I now consider my hometown.

I think that people who haven't been in small-population social contexts radically, radically underestimate just how strongly one's preferences are shaped by one's environment. Love is a sociological phenomenon, and I can't really explain it any better than that article does.

When you're living in a social context with fewer people, your sense of what makes an ideal relationship changes to fit the social context that you find yourself in. Maybe you won't have as much in common with your partner... and maybe that will be okay, and you will still enjoy the time you have together. Maybe there will be more things that annoy you about your partner... or, maybe not, since, having grown up in a similar restricted social context, you'll be more likely to share certain habits.

I'm not offering any rose-colored glasses here; life in a small community is only as good as the people around you, and people are not always good. But we people have a habit of growing and changing in accordance with our circumstances.