Some things could be counter acted with software (make desktop taskbar only visible when mouse reaches bottom of screen, etc.), but I would be interested in some real life data as to how long it would take for even burn out over the whole screen, till it drops as much, that the quality degrades to TFT level.

(there is a guy on Youtube who installed an OLED TV as his main monitor: https://www.youtube.com/watch?v=AXKhYH3BaIA&t=36s)