How does mass media make profit? and why is it necessary?

Mass media makes a lot of profit and the main source of this profit is the audience. As the number of audience increase for a particular mass media the profit increases. The reason behind this is it is not just the mass media that require a huge audience to entertain but the services and product that want to inform the public will prefer to advertise their product or service through a mass media which has more number of audience. Thus which ever media has more audience has more profit. Sometimes it is also depends on the type of audience that a mass media has their focus on. Secondly, mass media does need profit because so many machine and tool used in this mass media needs money and also it has to pay a large number of people who are involved in broadcasting of any media. So media requires profit.