I have never seen so many replied to comments, with no karma on a hugely active subreddit like r/CC

I just realised going through my profile that this subreddit is the only one I regular where most of my comments are untouched despite its activity.

I have over 100k karma across reddit, with at least 50% of my comments getting more than 1 karma, however on this subreddit it is more like 80% no activity, despite often getting responses.

I hadn't looked in to the way the xMOON system worked, but is it a total amount split, or is it something that is scalable? That would explain the lack of karma per comment that I have been seeing across the subreddit. If that is the case, doesn't that break the karma system that Reddit is based around?