trends in smartphones change very rapidly...2 years is a life's time in smartphone market.
hifi is the hot game of 2015.
in 2016, everyone is fighting on fingerprint and dual camera, hifi is forgoten.
in 2017 we can expect curved oled, zoom dual cam to be the buzz word.
after iphone 7, i bet headphone vendors will include dac in their new products as a common practice, and smartphone vendors are less motivated to include 3.5mm jack anymore.
Good analysis.