Why does the professor mention Rural Free Delivery and Parcel Post?

In the early years of the twentieth century, 60 percent of the American population was rural, and half of the nation’s towns and cities had fewer than ten thousand people. Up until that time, life on the farm was lonely, and farm families felt that they weren’t keeping up with the urban population, which had electric lights, telephones, and access to the latest goods in department stores. Farm families were isolated, often with limited funds, and few could afford the time or the expense of shopping in the city. But all of this changed with the introduction of the mail-order catalog.
In 1872, a Chicago merchant named Montgomery Ward began sending copies of a catalog to thousands of farmers in the Midwest. The catalog was 280 pages long and offered farm families the opportunity to order any of the goods listed in it by mail. This is how Montgomery Ward and Company became the nation’s first mail-order company. Ward had discovered something entirely new and profitable, a new method of conducting business. After that, the terms "mail-order house" and "mail-order catalog" were added to our vocabulary.
The most successful mail-order house was Sears and Roebuck, which entered the mail-order business in 1895. Just as Montgomery Ward had done with his catalog, Richard Sears advertised his products in catalogs that were sent to farm families. The Sears catalog sold food, clothing, machinery, tools, stoves-anything and everything a farm family might need.
The mail-order business spread rapidly, largely because of improvements in postal services. The post office established Rural Free Delivery in 1902 and Parcel Post in 1913. These new services meant that catalogs and goods would be delivered directly to the farm, so farmers didn’t have to drive several miles into town to pick up packages. These new services greatly contributed to the success of mail-order houses.
Rural Free Delivery also had great benefit for farm families. Families that had previously been isolated could now receive newspapers, magazines, and mail-order catalogs in their mailboxes. This contact with the outside world broke their isolation and changed the outlook of rural America. Thanks to the mail-order houses of Montgomery Ward and Sears and Roebuck, no farm was too isolated to be aware of the latest clothing, furniture, farm equipment, music, and literature.
The wide distribution of the Sears catalog had another interesting effect. The Sears catalog had a lot to do with the similarity of goods available nationwide. Of course, this was also due to the mass-production of goods. Mass-roduction techniques made it possible to create reasonable copies of, for example, high-priced clothing. The two factors working together-mass production and nationwide distributio-tended to minimize regional differences in clothing styles. This is why there was a general lack of class and regional distinction in American clothing. People believed that if clothing of the same design and brand was widely worn by many people, then this was a sign of its value.
By 1910, both men and women could buy every article of clothing, ready made, from mail-order catalogs like Sears. Sears didn’t pretend to be a leader in fashion, but it did try to provide what average Americans wanted. Women wanted to dress more fashionably and they welcomed new styles. For farm women, the pictures of the smiling women on the pages of the Sears catalog were as close as they came to outside contacts during the long winter months. And for immigrants who wanted to become Americans, the Sears catalog was a textbook. Here they learned how to dress, how to furnish their homes, and-some catalogs even had recipes and menus for holiday dinners  how to cook American food.