We should delegate "mmo historians" and give them a salary just to record significant or even ordinary social interactions or events! We already have some services such as 3d print of your avatar which is similar to an artist making a portrait.

How did we end up having historians in real life? How can we give similar incentive or motivation for mmos or other games?

Now that I thought of it, there's excellent coverage of what happens in e sports, e.g. "this team did this to beat that team", which also links back to the documentation of ancient wars.