> And the people they're both making money from, are people who think they have enough expertise + exposure to function as superforecasters — and who probably could function as superforecasters, in a market with fewer "sharks" in the pool — but who lose out simply because they were slightly less well-calibrated than whoever they were trading with.

This seems like a complicated way to say "suckers". Of course they don't usually self-identify as such and think they act rationally.