We've had Internet radio for almost 2 decades; it's called "podcasts". It's literally eaten "real" radio; NPR probably has more podcasts than broadcasts now.
That seems to support christopherslee's point. NPR already had what it needed institutionally to do podcasts people wanted to listen to and the reach to make sure they have a chance to reach an audience. I could start one and probably do okay because I already know a bit about audio engineering and marketing and can make my own music, but most people start from 0.
I thought they could be an add on to podcasts or radio shows where instead of having a phone bank or twitter feed, people listen in on clubhouse and then when picked by the host they get to talk or win tickets or whatnot.