Radio dominated the first half of the 20th century but the advent of affordable TV sets in the 1950s seemed to spell doom for the format. Yet, radio endured. Radio was able to create a distinct image for itself, separate from TV. I have own theories as to why (cars, transistor radios and the music industry) but nothing conclusive.
You can listen passively during work (household, cooking, construction work) or while driving. You often need your eyes. Also radio often plays music which doesn’t consume a lot of active thoughts. It depends a bit on the station though, some talk a lot and play less music.