One of the more bizarre trends of the past 10 years is to go out in public and see so many people with headphones on or in their ears. This is not related to ownership of portable music players, since everyone had a Walkman back in the good old days but did not wear it out in public so often -- hardly at all, in fact. Rather the change is in how people use the same kind of technology during a time of greater cocooning, namely to block out other people, turning would-be public spaces into hives of private cells.
The typical buyer may spend around $30, though a booming market for $100+ headphones now accounts for 6% of units sold. Someone who plunks down $50 for a pair of Skullcandy headphones is doing so partly for the fashionableness of the brand, but they also see something very utilitarian in them, i.e. the improvement in sound quality. According to a marketing report from NPD, sound quality was an important purchasing factor for 48% of all headphone buyers, and for 76% of the buyers of $100+ headphones.
And yet the music they're listening to is almost always an mp3 (or similar low-quality file like a streaming YouTube clip or even satellite radio), where 80% of the source data has been compressed out of existence. Or maybe using their phone to watch a movie or TV show that they downloaded from a file-sharing service, where again more than half the data on the original DVD has been compressed out. If they were so concerned with sound quality, they would be listening to vinyl or CDs, and watching on DVD or Blu-ray. No amount of headphone engineering can replace the data being read off the storage medium, once it's been gutted.
Another sign that the headphone craze is not driven by a true concern for sound quality is that even when they listen to music at home, it's over the cheapo speaker in their laptop or headphones. A basic boom box or stereo system with speakers isn't very expensive, and it wouldn't have to be very sophisticated at all to beat headphones for sound quality.
What they really value is the cocoonability of wearing headphones connected to an iPod, phone, or laptop. It's not quite accurate to say that they value "portability," as it is specifically the ability to isolate yourself from others while in public that they value.
You don't have to be a Luddite to feel repulsed by what's happened with consumer electronics in the past 10 years. Just 20 years ago, the norm was to listen to music from a high-quality medium like vinyl records, CDs, or FM radio, and coming out of a decent set of speakers, whether from a home stereo system, car stereo, or the set-up of a bar or nightclub. And nobody used consumer electronics to convert a public space where people are supposed to at least acknowledge each other, perhaps engage with one another, into a hive of cubicles.
On a final related note, I wonder if wearing sunglasses is more common now too. Meaning, a greater fraction of people owning them, and those who own them wearing them more frequently. Particularly within the past 10 years or so, it seems like a huge fraction of girls wear sunglasses regularly when the weather gets brighter. I don't remember seeing many girls like that at the mall in the '80s and early '90s, and I doubt that's an inaccurate memory. Being surrounded by so many people with un-seeable eyes is the kind of thing you notice.
Headphones, sunglasses, holding a phone or placing a laptop always in front of us like some shield... won't be long until everyone's wearing the scramble suits from A Scanner Darkly.