The Fediverse can only grow, I'm glad that it mostly seems to work the only problem I have is that on smaller instances you can't see the history of non-hosted communities as well as you have to add each community to the instance what is hard to find without using certain communities or just checking another instance.
It's probably due to the selecting 'Most Popular' meaning that it only finds the most upvoted thing on the instance. Instances as well as the Fediverse have grown so much adding more and more content over time but that does not always mean that everyone sees that one meme anymore making more modern posts have less traction. (At least from what I can think)