Hrag Vartanian, on the crowding that afflicts such museums as the Louvre, the Met, the Hermitage, the Tate, and the National Gallery (both U.S. and U.K.): “We need to break up the major museums. That may sound radical to some, but it’s an idea whose time has come. I’m suggesting not that museums sell off their collections but that more museums consider aggressively building outposts or prioritizing longer-term partnerships with smaller or newer institutions that could benefit from such relationships.”