Recently there was an article here on HN declaring that LCDs are on their way out now in favor of OLED. That doesn't seem true at all for the monitor market. The author doesn't even mention that both monitors are LCDs.
You don't want an OLED PC monitor because it will very quickly suffer from burn-in at the typical locations of taskbar and window controls.
As for burn-in, this doesn't seem to be an issue in smartphones for many years now, and monitors are also not normally used with damaging high brightness HDR content like OLED TVs. My guess would rather be that OLED monitors are too expensive, maybe because they have much higher PPI values than TVs. (A 55" 4k TV has only 80 PPI.)