When the producers of the new Broadway revival of Grease struck a deal with NBC to air a reality show in which viewers would pick the stage show’s leads, they figured that the TV exposure would be enough to boost their box office take through the roof. Think again: “Grease: You’re The One That I Want” has been trashed by critics, and is hemorrhaging viewers. Worse yet, the expected box office spike never materialized, and most working theatre types think the TV show cheapens their entire profession.