New York City may never sleep, but its tourist hot spots usually slow down quite a bit in the gloomy, gray depths of January. The crowds at the Metropolitan Museum of Art, its bastion of culture known internally just as “the Met,” usually thin out in midweek mornings, during the post-New Year’s hangover especially, so suffice to say it was astounding to see the penultimate day of a flagship exhibition absolutely packed on a dreary Thursday morning.