For most of the last century, AM radio is where new music broke. It was local due to the limited range (depending upon the wattage of the station) and reflected the musical tastes of the area (not to mention open to local music) as a result. In fact, many of the most enduring hits and superstars were made when a small station in Maryland, or Pittsburgh, or Chicago, or Florida began playing a record that then slowly caught on with the rest of the country.
Sadly, the days of AM radio may be coming to a close.
One of the reasons is that electric cars like the Tesla Model X or BMW i3 don't install them since the AM reception is impossible due to the internal electrical noise of the car. That said, the demand for AM has been way down as almost everywhere in the country AM stations are almost always at the bottom of the Arbitron ratings. It's now the place for news, talk radio and sports, but not music. In fact, even sports is abandoning the band for FM.
In Europe, AM stations are being rapidly shut down on a national scale. Norway and Germany have discontinued all AM broadcasting, and even perennial heavyweights like Radio Luxembourg and Armed Forces Radio have shut down their AM signals.
In some cases, even FM may go dark as many countries opt for Digital Audio Broadcasting instead.
What you'll see in cars more and more is an internet connection which will enable you to connect to a much greater variety of online stations from around the world. In fact, the idea of "stations" may fall to history as well, since with no broadcast frequency to worry about (nor government issued wattage limits), only the URLs are necessary. Restrictions on what to play may be looser too.
While on the face of it this seems like an exciting idea, losing the local musical flavor of radio is a sad twist of fate that will ultimately be bad for musicians, artists and bands everywhere. The cultivation of local talent and the ability to give them that first break will be sorely missed.