/r/videos used to be a default and supposedly has millions of subscribers, but when I was still on reddit you'd regularly see content with 100 upvotes reach the top of the subreddit and maybe 10 comments. Often this was on bot reposts.
Their numbers should be take with a huge grain of salt.
I think it's fine. Lemmy was actually nicer with less users. Now it grew a bit and all the trolls also came along. If it becomes huge, it will probably lose most of its charm.
Bigger is actually not better sometimes I think.
I'm happy right now with it. But sure, mostly memes and Linux stuff which I like, so...