How did advertising come to support radio economics?

Radio advertising is affordable and has proven to be the most effective medium for delivery of advertisements to a target market. There are many reasons for the radio being an effective source of advertising and make sure that the widest range of people can be exposed to it. People wake up to the radio in the morning, listen to it to and from work, hear it at the workplace, and stay up to listen to late night talk shows. Radio spots can require a smaller a smaller budget than advertising in newspapers and magazines. While T.V. pulls the big audience, it's still radio thats there everywhere all day and all night. Maybe the most beneficial use of radio advertising is is the effectiveness of ads on listeners. Radio is perceived as the most intimate of advertising mediums, because people are often alone when listening to the radio, either from work or when they are just bored at home. Maybe the reason why people are more accepting of radio advertising as opposed to other forms is because people tend to develop a personal relationship with radio stations, shows, or presenters, more so than than with television.