I’m simplifying here, but essentially no one has figured out how to make OLED panels affordable at a reasonable form factor for monitors yet. The type of panels used in phones (and tablets/laptops) are very different from those used in TVs. LG is making inroads with their 42 C2s, but those will also have a high price and is still way too big for normal monitor use cases.
There's a 34" ultrawide Alienware QD-OLED (Samsung's new OLED tech for TV panels) coming this year for $1300, which is still expensive but nowhere near as expensive as monitor OLEDs have been.
I seem to recall smartphone OLED screens being made by one company and tv sized OLED screens being made by another, with the smartphone OLEDs being better with burn-in but very difficult to scale up
There are no high PPI TV OLED that fits the monitor market. TV OLED panel ( or WOLED by LG ) only gets down to ~40" TV size and with 4K resolution. Meaning you get sub 2K resolution in 20-30" size.
Smartphone OLED by Samsung or BOE or other maker are too expensive to scale to Computer monitor size.
And burn in. OLED just isn't well suited for computer monitor usage. ( Apart from QD-OLED )
My understanding: They still can't get big enough sheets without defects. The bigger the end product, the more failed sheets have to be thrown out or cut down for smaller displays, and the price rises rapidly because double the diagonal means 4x the pixels.
They can make sheets large enough for TVs and both TVs and phones do come with high enough pixel counts for monitors. You don't need phone pixel densities on their monitor but TV pixel densities might be too low.
