The phenomenon you describe would indeed be a concern, if it reflected the day-to-day reality of the sub - while we do get very popular META threads on occasion, it's a relatively rare occurrence, while 2-3 history questions a day tend to get significant attention. While there are doubtless dynamics involved that means the viral ceiling of META threads is higher (such as everyone being able to comment, or topicality), so long as the history is getting the attention most of the time, we're not too fussed. Even the highest upvoted threads will only linger for a day or so - so long as tomorrow's most popular thread is about medieval toothpicks or whatever, the actual upvote count isn't that important.

On the flipside, META threads do serve a vital purpose for the community. Our rules very strictly clamp down on users' ability to express themselves in most threads - we stop people commenting on the topic at hand most of the time, let alone more abstract concerns about moderation and the state of the forum. While the subreddit is functionally run as a dictatorship, we do try and be a responsive dictatorship, and that means providing private and public routes for all users to make their voices heard. While we don't always agree with the premise of META threads or the comments they contain, they serve an important purpose in ensuring the sub stays on track.

I think you are missing a vital clue. The reason those are the highest voted questions and they also are META is because people on Reddit at large that are not history buffs would also be curious to ask and answer those questions. META topics have have a wider appeal than actual historical data, unfortunately. Most Reddit users do not care which comb Abraham Linkin Park used on his beard, but they are curious as to if ancient people believed in Enki the same way we "believe" in Santa.

Mostly? Who cares?

I would rather that reddit have somewhat different interests than it does for a whole lot of reasons, but the point of AskHistorians isn't maximizing one's internet score. That reddit is singularly focused on karma counts as a mark for quality is certainly a problem, probably an unrecoverable one, but even if it were not I don't think anything in the sub's power to do would change it meaningfully.

I don't know, but I'm glad we have this meta post to discuss the issue.

It's a sign of a clearly healthy moderation culture that encourages reflection on moderation and meta-standards. Sincerely!