I hear this all the time. Perhaps demand follows an 80/20% rule because my experience doesn't align with this.

I'm a man, 40 years, polyamorous, yet I have zero problems finding people to date. On average, I have more partners than the women I often date. I agree that Tinder and such are highly skewed, but it doesn't make it useful for any gender. In-person (events, social groups, etc), I find there are a large number of people who actively want to date me and spend time with me.

I don't see a clear gender divide in dating opportunities in my personal experience. I haven't been able to figure out what is unique about my experience vs the majority of men. I am not a "10" in any way; I just have a lot of hobbies.