In some ways, this is merely a natural outcome of Art in the Age of Mechanical Reproduction. Photographs and prints are made to be reproduced, and so lose the unique sense of encounter that one gets when one sees the "original". Certainly, I love that frisson of seeing a famous painting in person. The other side of the coin, though, is the disappointment of seeing it in person. For example, I am always repulsed by how grey and dirty Mondrians and Malevichs look in real life, compared to the crisp whites in postcard and textbook lithographs. However, I suspect that is a reaction cultivated by the crispness of the inauthentic copy with which we are surrounded - no doubt, those who have only experienced Venice in Las Vegas are also repulsed by the patina of age and dirt on the real thing!
But back to the museum mirroring: after some thought, I realised that this was quite a cunning thing to do in order to placate tourists. Most visitors to New York will not, I suspect, do the sort of blitzkrieg tour of all the museums and galleries, as I do. Due in large part to high admission fees, and a lack of time, they will choose one or two to visit, and be satisfied with that. By providing them with the ability to see the Picasso they missed at the Met, MOMA gives tourists a chance to brag that they have ticked that box; alternatively, by mounting a show of objects associated with King Tut, the Met can bring in interested visitors who have come to NY to see the blockbuster King Tut show, as well as satisfy those who cannot cough up the ridiculous admission fees for that.
It's a clever marketing scheme, and it probably works. It does, however, raise a red flag for me in terms of how art is commodified. If it becomes a checklist of big names one goes to visit, where is the accident of the unexpected discovery of the new?