I guess it would have had to have been a resignation. Even years ago, everyone made jokes about Ben Croshaw being the only marketable talent at Escapist. I originally knew him from the Chzo games he made in Adventure Game Studio.
The Zero Punctuation format had run its course. I'm sure he was sick of it, whatever else was going on behind the scenes. Whenever they tried to pair him up with other employees (Jim Sterling, Jack Packard) there didn't seem to be much chemistry.
I did still check in to hear his impressions of games, although I took a long time to play the Dead Space series based on his criticism of how the series approached horror, and Dead Space 2 is fantastic. (The series as a whole is, despite some issues with 3.)
On the other hand, I'm pretty sure his reviews and remarks over the years led me to play some of my favorites, including Psychonauts, Thief 1&2, and Hitman: Blood Money, which I never would have done based on the earlier games in the series.