I have a slightly different opinion on this. That "meaningful consequence or tangible disincentive…" you mention is not just an online-phenomenon, and in my opinion is decreasing substantially in real-world discussions as well, mostly in terms of accuracy. Perhaps because of the really poor standard online discourse has been set over the last decade. Person A can say the same BS both in an online or a real life, and person B can judge the claim/reasoning too in both scenarios. Person A can also feel "really" sucky after an online interaction.
Proving/disproving a claim/assertion/conclusion requires reasoning, time, experience and a real willingness to reach The Truth. It is a constant effort towards excellence. Those elements are often missing, for varied reasons. Lack of time or resources, a vertiginous endless flow of information, unpreparedness to deal with a complex reality, lack of tools to analyze and judge a situation…Very few people seek straight manipulation. In some occasions, people misbehave, but it often occurs in contexts of polarization or hot/anarchic discussing. What there exist, are many people with huge egos, who have been equipped with a loudspeaker with unlimited volume power.
I (want to) believe that most of the online discourses that “suck” are a consequence of one of the most prosaic, deeply rooted in human nature, bad habits: lack of humility. The stupid/unprepared/unexperienced in a certain topic are cocksure; the intelligent/prepared/experienced are full of doubt, or not heard at all within the chaos and noise. Lies/misinformation ends up creating frustration (or even worse, conflicts). There was a time in which prestige, experience and knowledge were respected and trusted.
The difference is subtle, but it is less a matter of disincentivizing person A from displaying a poor way of discoursing, and more of vesting auctoritas in person B when she has consistently proved to deserve it. Drawing a parallelism, it is less of telling person A to shut up and go home, and more of letting person A know, “hey, listen to person B, she is closer to this”. Technology created an issue, technology must provide a solution :). This is what I found appealing about TrueStory!