That guys mistake was to go from 54k to 66k without an oil change, or at the least, no filter change, and not knowing what was in the crankcase to start with. Even the best Mobil-1 or Amsoil would be iffy at that mileage without knowing the history of the car.
I dont think sludge killed this engine, but I think the oil broke down, or failed. Theres only so much you can gather from their posts. I dont think there are any "sludge monster" engines these days, with the level of sophistication of the current oils, and with the highly refine engines of today that run hotter/cleaner.
But the guy seems happy now. Lets hope he maintains it well if he ever trades it, or, he can drive it without ever changing his oil again if he is to going to drive it till it quits, and then park it in his back yard for his kids to use as a playhouse. Its his choice. He did have the foresight to buy the extended maintenance, for what it helped him.