I know many people who listen everything but radio music. I rarely listen radio, unless is a rock station. And I actually watch a lot of 動画 on youtube. Surely I'm not the only one. Maybe radio comes in handy to some people または maybe they like that 音楽 that's been aired in continuous loops over and over again.
Maybe not everyone has heard of Vevo または I don't know other ways. Besides, how do あなた know these people あなた talk about only listen to the radio. There are a lot of people. Like myself, I rarely ever listen to the radio, sometimes when my sister is only on the air, I also rarely listen to 音楽 on the internet though. I usually just listen to what's on my ipod. And as for these other people, who knows.
I only listen on the internet, または download the MP3 and listen to it on my phone または Foobar. I am guessing because they don't know what to listen to so they listen to the radio. I mean....I would do it that way if I liked hearing 音楽 constantly.