Just as a brief update to my situation (which I posted about several months ago), the burn-in never went away for me, and I'm sure at this point it's permanent, but I also just stopped worrying about it. The TV's gonna burn in for me. For a bit, I was stressing about it so much, I wasn't enjoying what I wanted to, and I just realized that's not worth it. This TV was not abused, and just please be aware IF you watch channels with logos multiple hours a day or IF you play games and they have static HUD elements, especially reds/yellows, you REALLY CAN get burn-in even if you mix up content and just watch those channels/play those games a few hours a day. (Keep in mind, for Zelda, I put hundreds of hours in before I was finished with it. But never more than 3-4 hours at a time, and more often less like 1-2, with plenty of other content and days I didn't play at all in between. And on red/yellow/blue backgrounds, the hearts are quite noticeable if you're at all looking for them.
So, yes, I have two rows of Zelda hearts in the upper left hand corner and the beginning of a CNN logo in the lower right. I do try to vary content up and not leave anything static for huge amount of times, but as I game with this TV, that's not really practical, and I've since stopped worrying about it so much. I also didn't find decreasing brightness or other things that could have helped acceptable solutions, for me anyways - I like a bright picture. The TV's 2 years old, and along with some other minor issues (sound sync for one, though the latest firmware might have improved some of that - I still need to test more), I'll be considering a different model before too long. (Waiting to see if there's a new Sony Z this year, as the Z9D was one I was thinking about, so I'm curious what the rumored F might have.)
Even with its flaws, this was far from a bad TV and if I forget about the burn-in, it still has a really great picture in 98% of circumstances - it's just not a perfect TV either, and I really do feel like I was a little misled about burn-in, both from LG's advertising and an early article I read claiming OLED shouldn't be very susceptible to burn-in when considering a purchase (the latter being partially my fault for not doing more due diligence). All that said, I'd probably be hesitant as far as going OLED in the future, since I do game, and since I don't want to worry about HUD elements or static logos. The other technologies just make more sense for my uses.