Two important factors that changes industry in the 1920s that I would add are the emergence of nationally and/or regionally known and recognized chain stores (five-and-dimes, grocery chains, etc.) and the emergence of modern advertising techniques that began to link consumption of consumer goods with innate human desires and expectations for personal success and identity. Chain retail outlets capitalized on radio as a perfect vehicle for sending mass marketing messages to the larger public and also, on the new techniques developed by advertising agencies who worked largely with print media like popular magazines that appealed to a wide and broad public. It is really in the 1920s that we begin to see the creation of "national" American and Canadian cultures because of the developments that the decade brought in terms of mass media and new advertising techniques.
Two resources to check out would be:
Regina Blaszczyk, American Consumer Culture, 1865-2005: From Hearth to HDTV
Roland Marchand, Advertising the American Dream
Historians call the 1920 "roaring," because of the prosperity of that decade. There were many advancements in the 1920s. Let me name a few of them.
First, there was the mass production of many different technologies. For example, the car was mass produced and was now affordable for the middle class. Before 1920 only the rich possessed cars. By 1927, Ford sold 15 million model T cars. Here is another statistic that might help to show the power of mass production. In Canada there was about 300,000 cars registered in 1918. By 1929, there were nearly 2 million cars.
Second, radio was also mass produced during the 1920s; historians dub this time as the golden age of radio. And in 1925, electrical recording became available.
Third, Hollywood grew as silent films gave way to films with sound. People flocked to theaters.
Finally, in 1917, Charles Lindbergh became the first person to complete a non-stop transatlantic flight, which was to have great ramifications.