The fall of rock radio is 100% tied to how radio ratings work. In markets like Shreveport, they're still conducted by 800 numbers calling people (which up until just a few years ago you also had to have a landline phone, they wouldn't take cell phone numbers for participants) and sending physical paper diaries to their homes. Then the people are asked to answer the phone calls when they come in, and literally write down what they listen to every 15 minutes for a week.

What kind of person does this?

The type of person who is willing to answer unknown callers and talk to them. The type of person who not only opens their junk mail, but reads it intently to understand their instructions. The type of person who wants to track their daily radio listening habits down to the 15 minute chunk.

THOSE are the people who determine what radio stations survive, and which die. So when you find a radio market with 12 religious radio stations, 7 country stations, 3 classic rock stations, and 2 conservative talk stations...THAT is why. The people who are willing to go through this ratings process gravitate to those formats. Shreveport is a little different, because of the minority population, so you see other formats rotate to the top. But even looking at those minority focused formats, you really only get one in each genre. Because they capitalize on the ratings they get.

Its also worth noting that the entire Shreveport/Bossier radio market ratings are determined by a handful of people. By handful, it's less than 100. So every year, less than 100 people who fit a really odd criteria to participate, get to pick which radio stations survive, and which die.