Because it categorically doesn't, not side by side in regular/low light conditions. The per pixel illumination sees to that when viewing dark content such as star fields/space scenes, a flashlight in a dark room (so basically every horror film ever made), and anything else of that nature. OLED utterly destroys LCD in these situations, this isn't even subjective.
HOWEVER, add lots of ambient light in your environment, something like a nature programme, a colourful scene full of bright colours etc. then you will see a top-end FALD LCD pop more.