Don't know much about asymmetric degradation ...
I can tell you that OLEDs degrade over time. LG give's it's OLED about 100,000 hours till they are half as bright as they were when new. I imagine if you don't run your tv at full brightness, and for a reasonable number of hours a day, it will give you a lifetime of use.
That said, this brings us to a few questions I have yet to answer: if you run an OLED at 1/2 brightness do you loose color resolution and would HDR require you to raise the brightness again ... one may find that the 100,000 hour mark is really 25,000. Lastly ,.. on degradation ...
I do know that exposing an OLED tv to direct sunlight will ruin it ... UV rays degrade them quickly ... which brings us to the old saying:
hang it where the sun doesn't shine
