The lack of "opposing viewpoints" wasn't the deathly blow to radio, the Telecommunications Act of 1996 was. Among other things, the Act removed ownership restrictions. Prior to the Act there was a sensible limitation on the number of stations an entity could own and in how many markets. With this limitation swept aside the door to broadcast conglomeration was opened and a race toward the lowest common denominator began. Station ownership became concentrated in a few hands, ie Clear Channel, and program diversity shrank dramatically. Now in the US you'll hear the same programming, particularly music, in every city coast to coast. The broadcast companies effectively became the gatekeepers of the popular music industry. Satellite radio to some extent defied this new reality, but let's face the fact that satellite radio sounds like ass.
Analog radio will last longer than 15 years. A transition date will be set, then extended.