It seems you've got the question reversed - it should be: "Will 3D printing affect museums?" And the answer is yes, it already has. 3D printing makes it much easier to share natural objects, artifacts, and models. Some museums, like the Smithsonian, have embarked on a program of scanning things in their collections and sharing them with the world in virtual form. Anyone with a 3D printer can print one out. The technique is also being used in preparing exhibits, and in stocking the museum's gift stores.