Theory of Hubski time. Okay now what could one reason be for having less low-effort bullshit as you just mentioned. The fact there is no karma here. You don't upvote or downvote, you're not collecting imaginary internet points. You contribute, and fill up your hubwheel. Sure, you could make a lot of low-effort posts to fill that up but what does it get you? A badge to give to somebody else for their content. To me, that's a huge difference in philosophy from Reddit. Karma is entirely for the person making the content, there is no return for anybody else on the website besides yourself. Here, it allows you to say "hey - this post is worth giving something I have earned from contributing".
Off-topic, but just my 2-cents on that. You edited your post while I replied but I think my thoughts somewhat address what happens when Hubski grows. Plus with the way tagging, following users, and most recently following domains works, I think everything is suited towards having your own micro-chasm in a more in-depth way than what is currently found on Reddit.
Edit: thenewgreen I was one of the December newbies! Whooooooo.