In my city, there is a large correlation between being a minority and being poor. I imagine that when you're struggling to find housing and food, even if you *are* poly, going to a poly meet up group event and being an active and visible member of the poly community is not going to be your top priority.
Then there's this random statistic from the Pew Research Center:
"Of all the major racial and ethnic groups in the United States, black Americans are the most likely to report a formal religious affiliation. Even among those blacks who are unaffiliated, three-in-four belong to the "religious unaffiliated" category (that is, they say that religion is either somewhat or very important in their lives), compared with slightly more than one-third of the unaffiliated population overall."
So, religiosity could have a large impact too, I imagine.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.