Tell me, have you actually heard of someone that is a radio host? Because to be honest, I feel like there arent any "recognizable" ones.
In terms of popularity, radio is a relatively more nicher medium for things. Sure, its used for listening and discovering music on a wider level, and is a GREAT resource for news, but what else does the average person "use" radio for? The public would likely say "nothing else"... not unless you're British, of course.
From my limited knoweldge on British culture in the 1970s to 1980s, the radio, and specifically the DJs in the studio, seem to be highly famous in the reigon, almost as famous as a standard TV host (or as the UK calls them "presenters").