On one side it was the most important cause of the boom because it was showing everyone that there is more new and better products around for sale, because if they didn't have a TV or another piece of technology that shows you the advertisements they wouldn't know.
Also they advertised cars and baseball. People who like baseball would most likely buy a car just so they could go and watch baseball games. Most people went to the cinema in the 1920's. So the industries would earn more money.
But on the other hand it wasn't the most important cause of the boom because the Ford motor company sold 7 million cars in a year and once one person saw the car more people wanted one. Also people dont really listen to the adverts that come on in the cinema because usually they're boring so know one listens to them and they won't take any notice. Lastly on the radio when the adverts come on people usually turn it over as they are boring.
I do agree that it was the most important cause of the boom because if people like what they're hearing and what they're looking at they'll listen and then go out and buy what they