I do agree that comments get under-rewarded. Mainly because comments are usually upvoted by the authors. And as you said authors are also curators, and spending all voting power on comments wouldn't make sense and people use lower voting percentages on comments. I guess it has to do with overall engagement. If more people were engaging in comments that would be a huge success.

We can see it in trending posts, where usually engagement is healthier and comments do get engagement and upvotes.

In the past I have seen comments in trending. I think it had to do with sbd-burn project. Not sure if there is anything in the protocol that would prevent child comments to get to the trending.

If yours did make to the trending, it would be just fine. People can recognize substance and engagement.