Streaming music has got where it has today largely by being the future of retail and replacing the download model, which in turn replaced the CD model (though vestiges of both remain). That premium model will continue to be the beating heart of streaming revenues for the foreseeable future but will not be enough on its own. The next big opportunity for streaming is to become the future of radio, which incidentally is around double the size of the recorded music market. In doing so, it will be a classic case of disruptive insurgents stealing market share from long-standing incumbents.
Source: Radio Is Streaming’s Next Frontier | Music Industry Blog