OLED is on the Watch so I have to believe it's coming to iPhone soon. Maybe iPhone 7 or 8 when the physical home button is finally gone.
Well according to Displaymate, the GS6 screen is the best ever made for a Smartphone and OLED doesn't suffer from the problems it used to, just like how LCD has come a long way since the garbage it was in the 00s.
People just get too stuck in the past.