People didn't tune out of Kings, or another favorite whipping horse for one kind of poster, Threshold. They never tuned in in the first place. So BS explanations for why they tuned out betray an agenda. They did tune out for FlashForward, so bbser's can claim a win for their Braga hate. (Unless they remember that Braga had nothing to do with the series after the pilot.)
On the other hand, people did tune out from BattleStar Galactica. When people could still imagine it was a continuation of a fondly remembered series, the miniseries, it had an audience in excess of seven million, if I remember correctly. When they found out it was a shamelessly sensational exploitation of 9/11, its audience rapidly dropped. By the time losing in Iraq and Afghanistan made the new BSG look kind of lame and they switched to the fatuous fake religion, the BSG audience had tuned out big time. No one bothers to offer BS "explanations" for why the viewers tuned out. The new BSG was only a big success with critics.
Firefly never got a large audience, I would think for the obvious reason that cowboys in space is a hard sell, being, let's face it, kind of dumb. It didn't have a particularly big drop off, so there's no reason to blame Fox for episodes being aired out of order or preempted. Most people who bothered to check it out, liked it. It's not like they did a scheduling change, or delayed new episodes for a writers' strike.
There was once a comedy series called The Sandy Duncan Show which debuted to the top ten. Then the star developed a serious eye disease (they saved her vision, fortunately, as I recall.) After her recovery, the show returned to the air. The ratings slumped dramatically, and the show was canceled. With the illness it probably never even had a full season.
The moral of the story is that so-called reasons for losing audience can be ad hoc rationalizations, that there is an element of luck. If Sandy Duncan had stayed on the air, the show would have become a habit.
If you are going to try to explain audiences tuning out, it would be a good idea to actually talk about shows where the audiences tune out!
By the way, "boring" refers to a viewer's emotional state. It is no more an explanation than "I didn't like it."
PS The Closer is on tonight, which reminds of last week's episode. In it, Chief Pope mentions that when the department asked for full financial disclosure from narcotics squad members, they all quit! Not only do most people find it makes a difference whent he detective is not a cop, including cops, it is not even true that all cop shows are the same. Such scenes like that are why Kyra Sedgwick has so much trouble getting an Emmy. This is the first cop show where the characters may dislike Internal Affairs, but the show doesn't. (Mary McDonnell is trying to rebuild her reputation after BSG by working as Captain Raydor. Which name is probably an in joke.)
)
I'm a mean person. 
