If you you look at DJ's today and wonder why they are so popular, they just blend records. Then the Picture of the dj seems more like a pop thing then a profession.
Lets go back to the beginnings of the radio broadcast. Radio was the center of the livingroom. Families gathered around the radio in the evenings to hear the latest news. During the 40's this technology was a important thing to have. The radio DJ wasnt a profession yet, the workers were simply called radiostaff. They had 78rpm records and early magnetic tape to play pre-recorded media on the radio.
Fast forward to the 60's with the beatles era, new music was broadcasted. The 7inch vinylrecord became popular. Radio Djs became a thing. They played radiosingles. Youth culture made its way in the world. You had peoples in US listening to British popbands. Beastles, Rolling stones. The record was the thing for the new generation. But media wasnt still focused of youth culture yet. It was still for the older generations. The only thing the 60's generation could really know about new pop Music was to listen to radio to hear new music. The radio dj was often the same person who spoke on the air. Mixing wasnt a standard yet. The transitions were song-to-speech-to-song.
It was with disco that the smooth transitions became a thing. You had dj's mixing for a dancefloor in the 70's with audio mixers like urei's 1620. The dj's moved from the radio to the dancefloors were they established Music gengres by fusing different Music genres into new styles. Like house, hip hop techno and so on.
Dj's started to record mixtapes and the disc jockey was born as a music artist since of the unique musicality in the mixes. The music generation of the 70s was underground. The disc jockeys didnt need to work on the radio to be influencefull. The Dj's status as an icon was established.