It’s extremely difficult for me to avoid the conclusion that these super-gigantic collections represent an inefficient allocation of global resources. If 15 percent of the stuff on display at the Louvre vanished at random, the impact on the experience of visiting the museum in particular or Paris in general would be minimal. But in the majority of the cities of the world, that 15 percent would be the basis for an excellent new museum.
This touches on a longstanding debate about the purpose of museums in general. One school of thought holds that amassing “super-gigantic collections” is precisely the point of having “universal museums” like the Louvre, the British Museum, the Smithsonian, etc. The idea is that these institutions are the ones that have the resources to care for their collections properly, which can be quite a challenge with certain types of specimens, and that their locations in major cities and general cultural clout make the portions of their collections they display (necessarily a tiny fraction of the total) more accessible to more people than would be the case if they were scattered among numerous smaller museums. The result of this approach is that while most people go to the Louvre to see the Mona Lisa, whoever also wants to see the antiquities collections and so forth can do so all in one trip to Paris rather than having to go all over the world. This view was also traditionally associated with the less savory imperialist attitudes of the elites who founded these museums in the nineteenth century, of course, which is one of the major reasons that it’s not the only view out there these days.
The main opposing viewpoint is basically the one Yglesias takes: cultural treasures should be distributed more equitably, rather than amassed in a handful of huge museums. A more specific variant holds that these treasures should really be kept and displayed as close as possible to their places of origin, which is a viewpoint particularly held by the governments of countries like Greece, Italy, Egypt, and Peru, i.e., the places of origin of all that stuff being collected by the museums during their more overtly imperialistic eras. There have been some recent high-profile cases of these governments demanding (and in some cases getting) their stuff back from major museums. You also see this sort of thing within the US, especially with regard to archaeological collections. One of the main points of criticism of the Hyde Expedition at Chaco, for example, was that the artifacts were being shipped off to New York, to be kept by the American Museum of Natural History, rather than staying in New Mexico where they belonged. Tellingly, however, many of the most strident (and effective) critics of the Hyde excavations were closely associated with the Museum of New Mexico in Santa Fe, preeminently the founder of the museum, Edgar Lee Hewett. Although the dispute was often portrayed as between “looters” shipping the stuff off with no regard for its scholarly value and professional archaeologists who wanted to preserve it, it was in reality primarily a dispute between two sets of professional archaeologists with different institutional sponsors. Both groups wanted the sites to be excavated, and neither had excavation techniques that were up to modern standards. Both also wanted the artifacts to leave Chaco, too. It was really a matter of whether they went to New York or Santa Fe. Nobody wanted to leave the stuff at Chaco (except the Indians, of course, but in those days nobody with any power cared what they wanted). Hewett and the Santa Fe side ended up winning, and a few years after the AMNH gave up on Chaco for good Hewett began his own excavations there, only to be immediately pushed aside by Neil Judd and his institutional sponsor, the Smithsonian. Hewett did get his chance once Judd was done, and the institutions with which he was affiliated, including the University of New Mexico and the School of American Research in addition to the MNM, have dominated research at Chaco ever since.
This local approach generally sounds better when viewing these issues from a distance, I think, although it’s important to note that the upshot of the various institutions competing over Chaco was that the collections from excavations there are scattered all over the country with very few of them on public display. From the perspective of the residents of a given place, whichever approach results in more of the stuff being near them sounds good, however, and the impetus for the founding of local museums in places like New Mexico has to be understood in the context of the general spirit of boosterism and economic development that pervaded small western cities in the late nineteenth and early twentieth centuries, just as the universal museum concept resulted from the rapid growth of major industrial cities slightly earlier. From the perspective of the visitor, concentration has the virtue of reducing the number of trips necessary but with the potential for increasing the distance traveled, while dispersion has the opposite effects (all depending, of course, on where a given visitor lives). Basically, as with so many disputes, this one ultimately comes down to a clash of fundamental values. Thus, there isn’t really a “solution” to it, just the necessity in each specific context of deciding which values to prioritize.