Radio is a powerful medium. Unless you have your ears plugged, it’s hard to ignore, even if you just have it on in the background. Used properly, it gets into the listener’s head where it becomes “the theatre of the mind”, leaving lasting impressions there.
Unfortunately, many, or dare I say even most, marketers don’t understand how to use radio, and they therefore abuse it. This medium is terrible for conveying a lot of information in a short time. But what’s happened in the course of my career is that radio commercial lengths have become shorter (30 seconds is typical), and the number of selling points and contact details marketers want to convey has increased.