Include rational agents who don’t think others are lying
Money is worth more when you’re smarter, so this is positive-sum.
Unverifiable information from sellers without sufficient capital to fully support the bet required to get them their fair share also can’t be fully paid for their information, but the market can at least buy the information at a reduced price so that they can afford the bet. This is sad but seems inevitable.
Note that here, capital includes the trust other people have in you to not lie outright about having unverifiable information, enough to loan you money for this bet.
Gurkenglas comments on Information Markets