I Agree with the OP but Apple will never bring the 3.5 mm headphone jack back to an iPhone, however there are many alternatives available if you want to listen to high quality audio files (DSD, 24 bit etc) like the Fiio Q3 DAC/AMP which is specifically made for iPhones:
Portable headphone amps, supports up to 768K/32B and native DSD512, easily decoding high resolution music and get a lossless sound.
www.amazon.co.uk
Or maybe something smaller like the Fiio KA3 USB DAC:
KA3 is a tiny headphones amplifier, it comes equipped with a 3.5mm single-ended and a 4.4mm balanced, 2 headphone outputs. It equipped with high-performance flagship DAC, can support up to 32bit/768kHz and DSD512. You could use the KA3 mini headphone dac to connect with your smartphone(Android or...
www.amazon.co.uk
And for those who want a lightning audio adaptor that is much better than the trash £9 Apple version, then:
FiiO i1 Portable DAC and Amplifier for Apple Lightning Port with Built-in Microphone and IOS Remote Controls for iPhone/iPad and iPod -BlackThe FiiO i1 is an Apple MFi certified, digital-to-analog converter (DAC) and headphone amplifier designed for the Lightning connector. The digital audio sign...
www.amazon.co.uk
The first one will power high impedance headphones no problems, and the bottom 2 will still give decent power to your headphones.