There's been big improvements in the last couple of years, from what I understand. And phones (small displays) were the testbed. It is interesting that Apple won't be using OLED until the upcoming iPhone 8 later this year, and given their.. strictness.. there might have been a reason for that.
That's probably why there are literally zero OLED monitors you can buy for PC, yet. I hope that changes in the next 5 years though!
Certainly 2016 was the sweet spot to date for OLED in TVs, where the price got down to "reasonable" and the technology is getting to a mature place with all the bugs worked out.
That is a cool case, wish I could buy it even with infinite cash.. but the whole point of this exercise is to decouple the GPU upgrade cycle from the system upgrade cycle. So you can plug a monster GPU into any system and transform it.
Connecting a GPU via a cutting-edge, external 5 gigabytes/sec Thunderbolt 3 connection is where the action is! That's fascinating. Building a whole new PC system up is easy, it's common, it's just not ... interesting.