...most successful-in-all-metrics theory of everything...you'd have malcontents on whatever the year 40,000 version of YouTube is...

If the Theory of Everything is to be ultimately successful, it may have to somehow incorporate the dark reality that we seem to have a persistent, malcontent cohort lacking the ability to be happy, and committed to disseminating their unhappiness. The theory may have to effectively respond to them. I'm not sure what that Theory looks like. Perhaps there is no such Theory to be discovered; it's just a tragic, intractable flaw in human nature, which is why we might not make it to year 40,000. If we do, it seems like humanism has to effectively respond to anti-humanist humans.