That's not really a counterexample, at least not to the claim you're disagreeing with. He was not just lucky, but he was nonetheless quite lucky. If apparently solid ground had just given way under Jerzy Kukuczka or the terrain above him had come crashing down on his head, or the temperature had suddenly dropped a lot further, he still would have died, wouldn't he?
The lower part of that route was quite dangerous in terms of rock and ice fall, but that was mostly behind them once they reached the upper part. Crevasses don't just occur anywhere, and they were mostly on technical ground where it was a non-issue. Ridges can have cornices, but if you are paying attention, you can usually find a way to traverse the ridge in a safe place (this might be much slower/harder). Usually you use a rope on serious cornice terrain and you carefully choose how to run it so that it offers some safety, but big falls are definitely possible. They didn't have serious cornices on that route.
I do believe that Jerzy lived through that event due to his preparation/talent for handling extreme conditions and his mental focus (to keep warm when sitting in the snow all night, to not make mistakes after being out for so long). Piotrowski was no slouch, but he fell because he got sloppy. Perhaps his physiology was also somehow less robust. Note that lots of other people have died because of one night out in the same conditions, even following a comfortable tent-bound night of sleep and a day with food and water. These two were strung out from their big new route and after the second night of sitting in the snow shivering without food or water, they still broke trail up to the summit. It was after the third night out that Piotrowski finally got sloppy on the ice climbing.
