I use higher impedance headphones that the built-in amplifier doesn't power well enough. Therefore I use a separate amp/DAC that feeds through usb from my iPhon

I use higher impedance headphones that the built-in amplifier doesn't power well enough. Therefore I use a separate amp/DAC that feeds through usb from my iPhone. But this certainly describes a very limited subset of people who listen to music through headphones, and even though I don't use it much I wouldn't like to see the analog jack go away.