I wonder if OLEDs break down more or less independent of usage anyways like how a lithium ion battery can wear out faster from use, but is still wearing out even if you don't use it.

That's certainly the impression I've taken away from reading a bunch of articles on OLED displays. The failure rate is apparently still high enough (at decent yields) that they're not practical yet, and unlike back-lit LCD displays, individual pixels degrade at different rates, which is pretty bad for obvious reasons.

Yeah, I think blue breaks down the fastest color wise. I suppose it might be because the emitted light would have higher energy than red or green.