There's another aspect to this argument that hasn't been discussed yet, probably because this is an audio forum and not a chart forum ;). However, it's important to point out that not every year is the same in pop music. If you examine the charts, you'll find that there are some years where the radio is very open to new ideas, and other years where they basically play the same song over and over. We are currently in the latter. Airplay and Billboard charts were basically frozen for the first half of 2012. Now that they are finally moving, it's only changing to allow another single from the same artist to fill it's space! It also needs to be noted that people aren't interested in versatility in the top 40. It would be easy to explain this by an example: Rihanna totally smashed last year with We Found Love. Normally, an artist like her could release total garbage for the next single and still have it become a hit. She didn't release Garbage though, she released You Da One. This song is highly regarded by fans, everyone thought it would also smash. It flopped, though. The same thing happened to the third single, Talk That Talk. The problem was that You Da One and Talk That Talk are sonically different than We Found Love. People aren't interested in artists changing their style. Once they hear one hit from them, they want their second, third, and fourth hit to sound exactly the same. She is finally reaching success Where Have You Been, a carbon copy of We Found Love. Her chart run shocked many of us pop fans. Under normal circumstances, all four singles would have ruled the charts. However, the music industry is only interested in copy after copy right now.
This trend happens in music every few years. Radio's have their select few artists and only play their songs that have a certain sonic quality to them. Anything that varies from the status quo even a little bit doesn't become a hit. There are also times in pop music, though, where consumers are interested in something new and innovative. It's a cycle really. So pop doesn't always sound the same. There are times when it can be creative and different. We have just been in a cycle where everything has to sound the same over the past few years. If I had to guess, it's because the recession has people craving happy party music. Basically the same reason why bright neon colors have came back in fashion.
Edited by elegantlie - 7/7/12 at 8:34am