So, that's kinda just how meme culture works in larger communities. It's extremely iterative. What happened is all those old posters are still around, they just switched to making content using older templates, and reminiscing about their favorites of the past.

This is a pretty big wave, this isn't beans or something, this took over almost the whole Lemmyverse, so it'll probably leave a minor lingering popularity. My guess is it should mostly be passed in another couple days or so, when people start running a little lower on content. The number of good ones is large, but fundamentally finite.

Meme culture is less the standard human-herd behavior and something quicker and more unitary. It's best visualized as a huge flock of birds or school of fish. Who's in charge and where is it going? No clue. It's going there though.