Accusing the music industry of greed isn't much of a stretch. That doesn't mean the industry forfeits its rights. It isn't very nice to be greedy, but copyright law has nothing to do with nice. It's all about ownership. Broadcasts that go out over radio waves and broadcasts that go out over the Internet are quite different entities.
Radio implies an audience that is restricted in geographical terms.
It also implies an audience with relatively restricted choices. An online broadcast has no geographical restrictions. Much-hyped digital radio may someday bring us thousands of choices on our car radios, but for now most of us are restricted to a few dozen at most. There just isn't that much room on the dial. Don't get me wrong, there's only a finite audience out there that likes to listen to music in the format that radio stations use.