Or the pop fans are more loyal and buy the albums. If someone wants Justin Beiber to stop making the most sales they need to be as avid as his fan base!
You are talking about "Kiddies" buying music, that is a whole different ballgame than serious music collectors. How many of these "Phenoms" last the test of time? Not many so I do not take them seriously and pay no attention to their record sales whatsoever.(For example I bought "Machine Head" and "Abbey Road" when I was their age and I still play both of those albums.)
Shadow buying used is not always an option, and I for one am glad there are generous people in the world who love sharing great old recordings you cannot find anymore, they help keep music alive.
I find it amusing that some people think that because the way music is being distributed that somehow it's in "Danger" of going extinct, or their favorite artists are no longer going to record or play at all. Musicians love their art form, they write, play and perform mostly for that reason, some exceptions of course but it is the burning creative desire that drives them, and if they make a little money along the way that is a bonus.
I have a suggestion, go back to releasing vinyl only, take the USB turntables off the market and the software that allows you to rip/burn music. Shut down i-tunes and collect all the i-pods and burn them in a massive bonfire, then the record labels will be back where they want to be.