Pivot just couldn’t pivot fast enough. The small cable channel shuts down on Monday, ending its short life with the film “Good Night, and Good Luck,” the 2005 movie about Edward R. Murrow produced by Pivot owner Participant Media. The movie’s title is an appropriate farewell for Pivot, and perhaps also serves as a message for the cable industry in general — as more networks face an uncertain future in the wake of so-called “skinny bundles” (cable packages with fewer channels) and the growth of cord-cutting. […] The company is believed to have invested around $200 million into the enterprise,...