"And I think that at a certain point, after all the time and all the conjecture and everything that had kind of gone on surrounding this show, I think that Mitch just felt like it was time to let it go. It was best for the show"

Will Arnett's quote is referring to the program "Arrested Development" which he starred in. It appears that the program had been surrounded by a lot of speculation and discussion, which Mitch Hurwitz, the program's creator, felt that it was time to end it. This could be due to the truth that the show had actually been running for a long period of time and the speculation and guesswork had actually ended up being excessive for him to manage. It could also be that he felt that the show had actually run its course and that it was time to carry on to something else. In any case, it appears that Hurwitz felt that it was best for the program to end which it was time to let it go.