[Basshead Paul]

Is it the hardware? The software? Why Iphone and not other high-end phones like Nokia Lumia Icon for example?

 

[GREQ]

This could depend on your personal definition of an audiophile, and the density of iphones per person around your immediate population.
iphones aren't exactly uncommon, and since they do double up as decent music players and get replaced regularly (by those who can afford them) it doesn't make sense to buy a separate DAP unless you want to carry an extensive library of music around with you.
 
Personally I think the word 'audiophile' has lost much of it's meaning in the past few years, as it gets thrown around so much these days on the internet/digital-media to describe anyone wearing a flashy pair of headphones with a shiny red 'b' on the side. 
I'd much rather be called a headphone/audio-enthusiast/geek/nutter than an audiophile... it's becoming a dirty word for me as some of the greatest 'audiophiles' around are just being lumped together with rich ignorant consumers who just like to own fancy stuff and show off. 

 

[formula1]

Because they aren't real audiophiles 

 
Seriously, it's a matter of preference. I have used android smartphones with USB dac's and been happy. 

 

[Saoshyant]

I'd rather use a dap myself than my phone, but that's more due yo me not having data on my phone (I use a tablet for portable data, but don't always bring it), and storage can be an issue. No clue why you see more people use iphones than androids.