How often do they release new games?
Puzzle Agent 2 was a single-episode title, Hector was a PC port from an existing iPad game, and the Walking Dead is still in production.
Seems like they haven't done much in the last year and a half.
...okay,
according to wiki, they were working on BTTF at the time, and shortly afterward developed Law & Order and Jurassic Park. It says PA2 came out June 2011, Hector came out April-"Fall" 2011, and TWD started April 2012.
What that tells me is the reason why it feels like forever is because
I haven't bought a TTG season since Sam & Max S3. I'm not sure whether to count Puzzle Agent or Poker Night (I don't count PA2 because I only bought it on a Steam sale and haven't bothered to play it.) it is.