"They didn't get run over the last two times they ran across the freeway, so running across the freeway is perfectly safe."
They developed those methods of dealing with JVM and scheduler issues because those problems rose in prominence against the background of a zillion other problems. They became the longest poles, most worth spending time and effort on. But those other problems still exist, with more appearing every day. Yes, even without code change, because environments and workloads change too. Anyone who has actually been responsible for large complex systems, not just in the sense of working at the same team/company and riding the coat-tails of those who actually understood it, knows that they require continued attention and always will. Entropy exists.
