LEDs replaced CCFL tubes in backlighting. LED was still too dark until iPhone 4S or 5, but once it became bright enough and automatic brightness control matured

LEDs replaced CCFL tubes in backlighting. LED was still too dark until iPhone 4S or 5, but once it became bright enough and automatic brightness control matured, it quickly eliminated needs for transflective displays. Transflective displays are also generally "low quality" in eyes of regular consumers. That drives down margins and eliminate less flashy options.