I was a fan back when they first hit the scene and pioneered the whole "internet critic" subculture. Goofy and juvenile as they may be, I do have to give them credit for really setting a precedent for the current state of internet entertainment. I remember being completely incredulous back in 2008 in thinking "you can make money yelling at video games on the internet?! That's brilliant!".
However, I think the two of them ultimately ran their course. The current market of internet personalities is so vast and rich that AVGN and NC have unwittingly made themselves obsolete by the very people they inspired. Like, I have to admit I get more laughs out of any given episode of Game Grumps or Markiplier than AVGN has given me in the last few years. Not that I'm speaking ill of them or their talents, but really the only reason I'd continue to watch AVGN or NC is - pun somewhat intended - nostalgia.
Then again, I get the feeling that James Rolfe has been wanting to move on from AVGN for a long time. In addition to the sporadic production of episodes, he doesn't put nearly as much effort into the writing anymore and seems to focus more time on his out-of-character commentary and let's plays.