Probably 100 different technologies have been invented or conceived in the past 30 years that would be used for displays, according to their proponents. Three of them have ever reached market, none with less than a decade of development before doing so: plasma (aka PDP), LCD, and OLED (which has yet to be used for anything larger than a 20-something-inch broadcast monitor).
Billions of dollars has been invested in failed technologies. Whatever you saw might have burned through thousands or millions, but it probably never reached a prototype stage, let alone came close to production.
There is no difference in HDMI cables. If you can see the picture without visible dropouts or sparklies, the cable is working at 100%. No other cable will display a better version of that picture. You're simply wrong if you think there is a better digital cable than one that is already working.