This is what I've been pondering for a very long time. Fox might as well give Seth a break for a year, because they have nearly twenty unused, but finished Family Guy episodes to air. Most are horridly out-of-date anyways (one of the last airings included Lindsey Lohan still being heterosexual, as well as having a deaf women call Moviefone to get tickets to 300, but instead getting the Last Mimzy [both debuted in early 2007!]), we might as well expect a "cutting edge" reference to the iPhone or Superbad during the next episodes, whenever they air.
And this can't just all be victims of the strike. For many years prior, the Simpsons has begun the new production cycle BEFORE the end of the year. Family Guy aired at least twenty episodes in both of the first and second post-revival seasons. You can argue sweeps and ratings and all that, but that FG backlog is just unexcusable...