Some believe that faster hardware and smarter compilers will mean they don’t have to worry about their program’s performance. This belief is simply wrong, usually preached by lusers who claim BubbleSort is fast enough on their systems.
Do not confuse OptimizeNever with OptimizeLater. See also PrematureOptimization.
OptimizeNever is not always intentional. Sometimes you really mean to optimize, but you’ve got so many other things to do that it never really gets done. I believe this is what happened with some bits of MacOSX over the past years; fortunately, Apple’s learning to OptimizeNow.