Why did the radio advertising industry increase during the 1920's?

The radio advertising industry surged in the 1920s due to the widespread adoption of radio as a household medium, which transformed how people consumed news and entertainment. As radio stations began to proliferate, advertisers recognized the potential to reach large audiences in real-time, leading to innovative advertising strategies. Additionally, the post-World War I economic boom provided businesses with the capital to invest in advertising, further fueling the industry's growth. Overall, the combination of technological advancements and changing consumer behaviors created a fertile environment for radio advertising to flourish.