Probably because there aren't any waves going out, just trickles to keep numbers up (if that). Most of it now will be coming from media/streamer (or even their own...) giveaways.
It's moronic if you ask me, they should simply give access to those who give feedback in previous Alpha/Beta/PTR tests, and remove it from those who only login just to test [read: see if they like it or not - not bug test/give feedback] their spec and log out... if they even install it at all.