Yes but when was the last time we had this level of personalization with music groups from around the world? If 6 teenagers commited suicide over The Strokes, what would have happened? Maybe they get a blurb in a newspaper, and some magazine mentions them. Today, they get tweeted about, Facebooked about, they get their own theme music, their own hashtag.
I would further argue than an environment of Fanboyism leads to further fanboyism. Therefore, before the internet, a group of fanboys would have risen and fallen without anyone noticing. Today you can create Groups and forums, which then leads to further zaniness around the globe. Teenage girls have always been the most susceptible market in the world, from the rise of the Spice Girls to the Backstreet Boys to N'Sync. However they were kept out of the reach of the lives of every day fans. Today you actually KNOW when Justin Beiber takes a shit. You know where he is, because he tweets about it. You know what he does, because there are updates on Facebook.
This personalization has undoubtedly been fostered directly by companies who stand to make a LOT of money from these pop-stars. More T-shirts, more TV shows, more tickets, more ringtones.
So while I agree with you that the signs of extreme Fanboyism are old and timeless, I'm saying the methods and extent to which modern society has taken the fanboyism is quite a new extreme.
I mean artists like jimmy somerville, ELO, aretha franklin. Which are artists that when you tell people about them they're like "wait who?", I already know the most famous bands but J wanted to know about those not-so-famous artists that actually had pretty damn good music back in the day.
There are pro-active fans and reactive fans for all forms of arts. You can find the same case with movie purists, or book lovers. We need to find the pro-active ones to discuss with.