Nine years is a long time for any series. It is difficult to keep the writing at a high level the longer the series continues. That was obvious with this series by Season 9. The writers tried to update the subject matter to mid 1960's culture, probably in an effort to attract a younger audience. The results are almost comical. It was difficult to even watch, and the attempt to maintain suspense to the very end results in a largely unbelievable conclusion.