[damie-dee]

 
Quote:

because most people dont care about getting that extra sound quality out of their ipods.  most audio people are speaker people.  the headphone enthusiast community is rather small.

Agreed. My assessment is the majority aren't audiophiles, prefer speakers, and are not willing to pay a lot for high-end home audio. That mainly sums up why full-size headphone amps aren't mainstream.

 

[NamelessPFG]

I'd say it's because people can plug their headphones right into the source and its rudimentary amp, they get sound, and thus it's fine to them. They'd rather not deal with the complexity of another device in the chain.
 
I'll admit right now that the only reason I'm shopping around for headphone amps is that, when it comes to Stax, I NEED one for the headphones to even function. I can't just plug 'em into a sound card like a typical dynamic or ortho. (Unfortunately, the amps tend to cost just as much as the headphones/earspeakers themselves, which is a big reason for the steep barrier to entry.)
 
And, yes, I'm using a Lambda right now...with a transformer box fed by a big old receiver. That's more bulk on my computer desk than I'd like, and the receiver technically isn't mine.

 

[curtisinoc]

Interesting thread  . . .  I was thinking the same thing as the O.P.  I'm very new to this "audiophile thing".
 
I've always enjoyed listening to music on my computer but recently purchased headphones as my primary way of listening (wife wasn't too happy with my music blaring too loud) so I stumbled on this site while researching headphones.  I chose the ATH-M50's and have been happy with them plugged directly to the 3.5 mm headphone jack on the back of my iMac.  I thought "wow, headphone listening is so much better than over speakers!"
 
Then I continued to read this site (head-fi) and recently discovered what an external usb amp/dac was . . hmmmmmm, pretty interesting I thought (I've never even heard of one before a week ago).  Continued to read and I just couldn't resist the urge and curiosity . .  "how much better can my music sound with an amp/dac" instead of using my computer headphone jack??  After obsessive reading, research and asking questions on this site, I ordered the FiiO E10 which arrived yesterday.  
 
Again, I had a "wow!" moment and have been happily ignoring my wife, lost in my music . .

 

 (kidding of course).  I didn't realize that a relatively simple & inexpensive piece of equipment (I know that they can also be very expensive) as an amp/dac can make such a difference.
 
I am by no means an "audiophile" . .  yet, but I can definitely see how this can become an expensive, addicting hobby/obsession. 

 

[seslwr]

I think the simple answer to this question is that headphones have evolved into a portable product.  Ever since the advent of the Walkman, headphones have been all about portability.  Having additional components (i.e. amps) counters the purpose of headphones for many people.   Most people just want earbuds or iem's hooked up to an iPod or smartphone as their primary music listening setup.