(Revised! See the afterword below!) The recent box office success of The Avengers got me wondering: why don’t blockbusters ever start on the small-screen? Why can’t the stories behind these tentpole movies (which are often novels or comics) be reformatted episodically and aired as limited-run series? Wouldn’t advertisers be tripping over themselves to put their commercials in such a broadcast? Wasn’t the six-part Roots adaptation one of the highest-rated television events ever? That got me to running some numbers. Let’s imagine the final Harry Potter book as a 36-part series by arbitrarily splitting the story into the novel’s 36 chapters (grouping the epilogue in with the last chapter). Such a series would run nicely between the beginning of September and the end of May—the span of the normal broadcast TV season—even if the series took a week off for...