For years now, the Kennedy Center Honors have been devolving from an award that recognizes stellar achievement across a diverse and rich tradition of American arts into an entertainment-driven event that rewards star power and pop-culture cachet. Representatives of the wide range of traditional arts, including classical music, opera and ballet, have been slowly edged out until, it seemed, they were lucky to be represented with a single award among the five given out each year. This year even that toehold looks precarious. Of the five artists to receive the 2017 Kennedy Center Honors, only dancer and choreographer Carmen de...