[This is not a review of the movie, but the thoughs that came to mind during and after watching it.]
In the film, the U.S. (in reality it began with Britain) realizes that Hitler has stolen much European art and has decided to destroy it when defeat seems inevitable. The Monuments men, an unlikely sextet, end up saving most of the art, of course.
The most amazing thing in the movie was to see the government(s) acknowledging the cultural significance of art, and ultimately, its value.
This apparently ephemeral confluence is always ongoing, though in a far less dramatic way. The culture tacitly acknowledges the importance and sociological value Jettisoned art -- most of the time. Art disappears routinely. Jettisoned because it didn't sell, or replaced with something newer, or is disposed of when the artist dies. I personally know of two artists who left behind literally hundreds of unsold works and have witnessed many more going for pathetically low prices at garage sales,,,and others peering out of dumpsters. There are many inherent cruelties in the art world. Work that does not attract buyers, artists too shy to show, or to market themselves to advantage. Galleries have to turn a profit, etc.
Parents with enough disposable income or willing to sacrifice for schooling and materials for a budding artist to bloom...schools with arts departments and curricula...grants...scholarships...the landlords who let you make deposit in payments...friends who know you're starving and bring you food....museums, galleries art shows that bring the work to the public. There is a system there ensuring art is made and seen.
In the movie we learn that Hitler, like a fairy tale dragon, wanted all the art to himself, in a huge Speer-designed museum that luckily was never built. There is an analog between that and the nouveau billionaires keeping the big art fairs afloat, who by top notch art speculatively and lock it up in their estates or worse, in climate-controlled vaults, hidden from everyone.