Why do economics drive most media companies?

Everything, especially in America, is run by economics. Media companies are no different. The circulation of money keeps the cogs running, and makes the machine of a market economy working smoothly. In order to create interest for a product, it must be advertised to the public. Money must be spent on advertisements in order to make them interesting enough to catch the eye of a passerby, and garner enough interest to buy said product. It's an endless cycle. The money that is being spent on advertisements must be made back, and more, by the product it is selling. That gain in money will be (hopefully) spent on another product by the same company, and the same process will start over again.