Your not comparing apples to apples.. The 4k or higher display needs to fit int a small smaller footprint.. Pixel density matters and many examples cited here aren't retina displays.. I do not see so many retina displays in most other laptops either, so the windows camp is far behind in that space..
There is also a burn in issue which is very real on oled desktop and not much of an issue on a tv with moving images.. So I suspect they want to deal with that issue more then anything else.. menu bars, docks and things like that could burn into the oled displays.. I think this is the deal breaker with apple.. phone's/watches/iPads have more changing elements vs a desktop display..