THE recent announcement of a wrenching round of layoffs at the Metropolitan Museum of Art in New York has sent a shiver through the museum world. Yet as recently as March, the Met seemed to be on a roll, when it opened a flashy contemporary art annex, the Met Breuer.

Indeed, if you’ve thought at all about the fate of art museums in the 21st century, it is probably as a rare example of good news in difficult times. The San Francisco Museum of Modern Art has just opened a $305 million addition, creating what is described as the largest modern and contemporary art museum in the country. Last year, two high-profile museums opened in New York (the new $422 million Whitney building downtown) and in Los Angeles (the $140 million Broad).

The turmoil at the Met should be our cue to ask if all this “good news” is really the story of cultural triumph that it is made out to be. According to the Association of Art Museum Directors, for every $8 visitors spend at museums in North America, museums spend $55. So running a museum isn’t a great business, despite the crowds.

According to The Art Newspaper, close to $5 billion from 2007 to 2014 was spent in the United States on new expansions, more than the other 37 countries the newspaper examined put together. The United States is also, the publication notes, unique in the degree to which it funds culture through private philanthropy, rather than public money.