Just my two cents, but the drop in feedback on meme hasn't much affected my motivation. I use the kinkmeme primarily for inspiration, and after a prompt catches my eye, it isn't any different from writing fic based off of my own ideas. At that point, it mostly comes down to my own determination to finish. The slowing down doesn't really affect me either, since I've saved lots of prompts from past rounds. Of course, that's just me - other people seem to have quite different experiences.