At that point, you are paying for a tool. And you want your tool to be good. The site design maximizes time on site by minimizing the rate of information you can get. "Catching up" takes forever, compared to when most social media websites were chronological.

If I'm paying, I want something that maximizes my productivity. Imagine if adobe released an update that made something that took 2 steps into 7 steps, just to make sure you are spending a larger % of your day screwing around in Photoshop. There would be riots in the streets.