My LG 42" just went out. It was maybe only 7 years old. Sound was fine. Main lighting went out. It already had about 6 light diffuser covers fall of, so it had white spots with certain brightness levels. Hadn't taken apart yet to super glue back in place. Had a fantastic picture. In the TV's defense, it basically ran 24/7/365. It was never off. If we weren't home it stayed on for the dogs. So I guess it's short life was comparable to many more years under normal on/off times.
The OLED's are cool in that the entire picture screen is a mat of individual pixel lights that get "glued" to the back of the glass and that's you TV. If one light goes out, the whole mat is replaced. Can't fix a single pixel. It may have been LG, but first one I saw after they came out, was a curved 55" glass, mounted on a harmon kardon sound bar base. That one was about $6 grand at the time.