I kind of expected some people to start instances for mostly just making accounts (some of which I have seen), and for other people to make instances just for community hosting and disallow account creation (and afaik this hasn’t been done to any appreciable degree). I’m not sure this is even possible or functionally useful with the way lemmy currently works for community creation and stuff, so maybe that’s why it didn’t happen.
Honestly I even expected some instances to pop up with the sole intent and purpose of serving one community, but even stuff like the startrek instance have account creation available.
Maybe it’s because lemmy is so new for people. Niche instances would rather host accounts than scare users away in an effort to get them to sign up elsewhere.