No, it's not easier. Anywhere you read that is based on a lot of bogus speculation using technology that doesn't exist.
The backplanes are the same as LCDs, the color filter layers (on LG's OLED at least) are nearly the same as LCDs, the middle layer is proving hard to build at any size. Future OLED techniques don't even exist yet and they won't be 80" and up for quite some time.
On the other hand, Sharp is showing it's really, really easy to make 80" LCDs.
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.