This cannot be all of it. I've never been a Reddit user besides the occasional research e.g. in the wiki of /r/BuildAPC. But even I am put off by the new design. Possible explanations:

1. It looks like a mobile app. I hate most of the mobile ecosystem for its horrible information density and dark UI patterns.

2. You cannot find shit. The only way to open a subreddit's wiki in the new UI is to append "/wiki" to the URL, from what I can tell.

3. It looks like a social network (i.e. a waste of time) and less like a forum/message board (i.e. a productive community).