Well, let's say you've got millions of classes that all perform the same operation. Now you refactor those millions of classes to rely on a handful of classes

Well, let's say you've got millions of classes that all perform the same operation. Now you refactor those millions of classes to rely on a handful of classes to perform those common operations. Now you've just made it easier to eventually refactor those few remaining classes into something nicer, cleaner, more efficient. Sure, you're just shifting the source of pollution in the interim, but once cars are no longer polluting, changing the source they charge from is the last roadblock to removing those emissions from the system.