Major radio markets in the United States feature dozens of channels, each specializing on one genre of music or talk, with the advertising focused on the segment of the population that will most likely be reached by that type of music or talk. 

As a potential advertiser, that is a good way to focus on a potential market.

I am currently in Japan.  When I lived here, and when I have visited other countries, I was always surprised at the limited number of radio stations available in each city compared to what we have in the US.  Each market has only 2-3 major FM (and an equal number of AM) channels.

The radio station that we have been listening to recently (radio i) plays a very diverse selection of music.  Occasionally there are special programs such as: jazz hour, hip-hop hour, 1970s Tuesday; but in general, the music styles are really mixed up during the day.  (Lots of deep cuts too!  Coolest song today was Blondie's "The Tide is High" live.  I also heard a really cool Turkish song today.)

I find this type of radio to be a lot more entertaining than the genre-specific radio that we have in the United States.  It gives me a chance to hear singers and songs that I wouldn't normally hear if I were to stick to my favorite genre-specific channel.

Unfortunately it is unlikely that we'll ever have such a radio station in the US.  It doesn't make sense to not focus on a genre.  I will have to just enjoy what I have while I am travelling.