I believe "quad" failed because in part because there were compatibility issues /this quad cartridge wouldn't play another mfg's quad disc.The economy also played its part. Heck even 8 track was better than cassette.Larger tape/faster speed. Reg.DVD is the fastest growing format.Check the floor space at your local Blockbuster. There is little reason for mainstream America to go for SACD,or DVD-A.Now back to CDs,they will be here for a much longer time.The improvements in cd playback are worth the price to those with large collections.A good transport/a good dac are worth acquiring if you are in this group ; Those pursuing the absolute sound from their collections.