At a guess, SE has been looking at statistics about 'what is popular' and 'what is not so popular' and putting resources into producing more of the popular content.

I enjoyed the Postmoogle content. I can't see it going anywhere else, since the storyline had a start and a definitive finish back in ARR.

At a guess, the content a majority of people are enjoying is the Tales of Wonder, which appears to be continuing to this day.