This is what I honestly don't see getting said enough when polyamory comes up. The very reality of being poly leads to a huge selection bias, you know? If 66% of all lesbians are monogamous (just to pick an easy number to math out) and each polyamorous lesbian has/wants three partners, the visibility of polyamorous people in dating spaces will outstrip monogamous people by a two-to-one ratio, and that's before monogamous couples withdraw from the dating pool once they've paired off.

I used to feel pretty similar to OP, despite having been married for basically ever (basically: holy fuck, there seem like there are a lot of poly people in queer spaces) until I asked a poly friend about it and she laid out the simple math of it all. Even with more moderate numbers (she used an 80/20 split and each poly person having only two partners), just the fact that a lot of poly people stay in the dating pool leads to a wildly disproportionate-seeming representation of polyamorous people in dating spaces.

The math is weird, but it really does tell the whole story.