Combine Internet radio programming with WiMax and there is no discernable difference between the latter combination and what an AM or FM station provides to a listener. (Of course, this scenario will only be complete when vehicles come with radios that are Internet-capable which I'm sure is already in the pipeline as well.)
Terrestrial radio once had a lock on a delivery method defined by a limited spectrum of frequencies. That will no longer be the case.
Its the Programming, Stupid
Now, for any Internet radio station using WiMax (or any other future technology) to succeed on a scale of an established AM or FM, it will require either exceptional programming or at least alternative programming which fills needs not being served.
But, Internet radio stations can operate on low overhead which means they can also take more chances in specialized programming. They do not need as big an audience as a terrestrial station to be successful.
An Internet radio station also doesnt need 12 minutes of commercials each hour to be profitable, like many AM and FM operations.
Automation and helper software is easily affordable to any Internet programmer to help run a station 24/7 with live DJs or recorded voice-tracks.
For these and other reasons, the playing field may actually tip toward the Internet programmers.