Ivins, William M. ""Ornament" and the Sources of Design in the Decorative Arts." The Metropolitan Museum of Art Bulletin 13, no. 2 (1918): 35-41

The difference between Design and Craftsmanship as I understood from context clues from the text, reflects that Design would be the ability to visualize an idea and transfer it in a plan of execution, Craftsmanship is the action of fiscally executing with your hands that idea. The analogy used about musicians and composers apply to do design and crafts since not all designers can craft their creation to a real live model.
As human technology develops the craftsmanship of certain objects become easier and something that the artist considers but does not stress about. This leads to concentrating more in the design of the art than the execution of it. As mass production started the concept of what was fine art and what was something that wasn't unique and recreated a numerous of times chanced. Some styles have been preserved for very exclusive display, and other have been used to sell in large quantities to users and they all share the same style.
Hepplewhite, Chippendale, and Sheraton where English designers trained as cabinet makers and their actual pieces design by them are unknown.The three of them published pattern books that in a way help their field and made them well-know.The author mentions the impotence of the collection and study of drawings, prints, and book decorations because he implies that it will help understand the change and improvement of ornament, and also could be the cause of inspection for future designs.

Museums relate to the idea of the collection and study of art since is a place where art is been preserved and exhibited for this specific  purpose.
In my personal experience when I visit a museum I find myself thinking about the art. If a piece interested me I move closer and wander how was it made how the artist created and why, what was his or her inspiration. I often find inspiration to experiment and go out the my comfort zone.The internet is another source of inspiration for me. Specially more accessible and resourceful. When it comes to a museum you have certain limitations. There is the Art the name of the artist and often a statement. In the internet I could find the piece and interview with the arts to know his/her reasons behind the piece. It's a wonderful tool to learn techniques of craftsmanship as well and apply it to your own design. As well as a way to get feedback of your work from an audience. It's a fast and accessible tool, but you will never have the tangible work you find at a museum.
The main Idea I understood across in this writing was that craftsmanship has been eroded over the years due to the advancement of technology through the years. Even though with some forms of art the craftsmanship has been the same since early years. The author wrote the article to emphasize the importance in the study and conservation of craftsmanship and design.