I encourage you not to look at one poly party and assume that what you saw there makes up the entire poly community in your city/area/whatever. There might have a been a terrific concert that night and that's where all the twenty-somethings went.
I recently went to my first poly meeting. I was so pleased to see the age range from young 20's to grandparents. And there was a lot of talk about all the people that were not present. My impression is that lots of poly people have very active social lives, and any given party night they might have something much more interesting to do. (or they might be having a surgery, or a trip to the ER, or a baby, or a family obligation)
I recently met someone at a different social group I belong to. He's written the whole thing off on his (self-fulfilling prophecy) observation that everyone was 'old' and 'not interested in' what he was interested in. I found it sad.
Love is that condition in which the happiness of another person is essential to your own...
Robert A. Heinlein
Me: female, bi, (formerly hinge of a vee)
with FirstBoyFriend (FBF)(moderately long-distance)
and no longer with CurrentBoyFriend (CBF)(who lives in the apartment building next door)