I have the same correlation (high writing output = low fic consumption), but I think the causality goes the other way for me: when I'm having a really good writing day/streak, I don't want to read fic, because I don't want someone else's story in my head, I want my story in my head. When writing is going well, I spend a lot of my not-writing time during the day thinking about my story. It feels like a live thing, and I don't want to uproot and displace it with someone else's.

Oct 2: 500 words on a new story (incidentally throwing out the bad couple hundred words I had before).