It looks like the main clause of decline is that spontaneous top-level postings are not enough to make up for the loss of the enormous subsidy of a good writer posting as a full-time job.

I think LW's high standards make the activation energy for writing new posts really high. I have lots of ideas for new posts, but when it comes to actually writing them, I think to myself "is this really something LW wants to read", "is this going to make me look like an idiot", etc. I've written a few reddit self posts in the past few weeks, and it was interesting to notice how much lower my activation energy was for submitting to reddit than to LW. It's almost as though I have an ugh field around writing LW posts.

Sure, you probably want people to have this high activation energy to a certain extent; it's a good way to keep the quality high. But if we want more spontaneous top-level postings, maybe we should experiment with trying to shift the activation energy parameter downwards a bit and looking for a sweet spot.

For example, one idea is to frame the moderation system as more of a filtering system than a punishment/reward system: "It's OK to write a lame post, because if you do, it'll just get voted down and no one will read it."

Another idea is to recognize that a given user's prediction of how much LW will like their post is probably going to be terrible, and tell people that if you never get voted down, you're not submitting enough.

I think the punishment of getting voted down is way more salient for me than the reward of getting voted up, and maybe I'm not the only one who's wired this way.