While your experience is valid, just to give a counterpoint: I've gotta Lots of Treats, some of them creeping close to 10k and combined in the 40k range and I still commented within 48 hours. I never lie in comments, so the fics I had less to say about I just said less, and the ones that I super loved got multiple comment boxes. I had a great time and would love for it to happen every exchange. People are different and there's no way to know unless you ask or maybe do some inferences on their comment timestamps. Commenting is fun for me, I read widely across the collection anyway so leaving Lots of Comments is something I'm already doing, and my reputation is still solid even though I don't force myself to leave the same comments on all fics regardless of quality. And yes, the fics that aren't great in hindsight definitely got an assist for being a part of a Lot of Treats and my goodwill was high. The halo effect of the amazing fics helped shine the unpolished.