That's a weird thing to say unless the pixel density is your one and only measure. Regardless of that, the posterization should be perfectly visible on a 2012 FullHD monitor, or even a 1366x768 TN screen of a decade-old laptop. Most commenters here are probably viewing the pictures on a scale different from 1:1.
Is it though? We now have OLED TVs and OLED smartphones.
Where's our OLED PC monitors?
On every measure, if you care about colors/contrast/black+white levels/resolution/density, the average computer monitor has fallen far behind.
You can't even buy a smartphone that has a panel half as bad as most PC monitors on the market. And, at least in my area, you'd actually have to go to a lot of effort to find a non-4k TV.
https://www.displayninja.com/oled-monitor-list/
Mainly targeted towards the gaming market at the moment.
- Framerate - Response time - Adaptive sync - (how prone to burn-in is OLED? Monitors often have way more static images to TVs)
I assume combing these all might just make it more expensive than just individually each feature
The much more complicated electronics plus Supply & Demand. Demand for TVs should be way higher then for high end monitors.
https://computers.scorptec.com.au/computer/Oled-Monitor
They've been around for years.
PC monitors have been improving constantly with high refresh rates, local dimming HDR + 10 bit color, adaptive sync, OLED and more.