I imagine its stuff they had in the works but couldnt finish before release, so technically not new content?

Because lots other people are.

It’s called a network effect and it’s the same reason everyone is on TikTok or Facebook or here. Like it or not when I started my project (a few months ago) people told me “you need to create a Twitter account, that’s where the people are”. I did, only post updates to the project, don’t use it to actually follow people, but I still have a few dozens followers.