Choosing the mona lisa is an interesting example because it’s pretty unremarkable as a painting, and most of its fame comes from having been stolen, rather than its artistic merits. Certainly making it larger would be helpful practically, given how small and crowded the space they show it in is, but would miss the mark entirely on why people want to see it, since wouldn’t be the actual object that was the subject of the heist. Most of why I go to art museums, though, is to understand the progression of the conversation about Art that takes place on canvas over the centuries, and having a “better quality” reproduction would hinder, rather than help me, as I want to know what Kandinsky and Mondrian had to say about space and rhythm more than I want to see some kind of idealized iteration on their most famous works.