ULTRA HD or 4K ACCCEPTANCE will HINGE on being EXCITED ABOUT VISUAL-AUDIO DIFFERENCES
Since the 1960's as an Audiophile 'nut', audio was constantly being improved with BETTER speakers (Altec Lansing 'Voice of Theater' from custom designed EV 3-way speakers) and BETTER amp/pre-amps (Mac tube amp/preamp to Marantz transistor receiver amplifier), then in 1970's with advent of LASER Disc players (Pioneer Elite system, including Monitor and Laser Disc player) enjoying the TREMENDOUS differences from VHS tapes (professional Sony decks) to what LASER DISC produced.
Later DVD and improved receiver design eventually phased out expensive LASER disc player and led to battle between HD dvd format and Blu-Ray disc format (won out due to superior specs, more data per disc, etc.- Sony gets even for Betamax vs VHS fiasco). Television is a saturated industry, but initial 720p HD television gave way to 1080p TV's despite the fact where sometimes, depending on the TV/manufacturer being used, it was hard to 'TELL' the 'improvement' of 1080p over 720p specs for HIGH DEF television.
Blu-Ray as the only true 1080p SOURCE material, where OTA television providing only 1080i spec viewing, required time to gain general acceptance and wide spread purchase of the equipment needed, requiring the lowering on BR costs, Discs and Players to make this happen.
IF 4K is truly so much better than 1080p and requires replacement of TV, AV Receiver, and BR player; basically everything from TV down to and including the HDMI cords, the Consumer must be a able to SEE the differences AND become seriously EXCITED OVER THE DIFFERENCES, to the point where 4K overcomes their normal reluctance to spend the $$$$$$ required.
IF and WHEN 4K ever does gain widespread acceptance and use; this reviewer believes it will take a LONG LONG time. davzway