I'm a programmer so to me this brings to mind the idea of classes and subclasses. A program is implemented by having a set of classes. The classes can be organized into a class-hierarchy where they inherit methods from their ancestor-classes.

Now assume originally you did not have the feature of inheritance in your programming language so you would just create all the classes you need without orgnizing them into an inheritance-tree. Then you upgraded to a language that doe shave inheritance and you wanted to refactor your program to omit duplicate definitions of methods.

What kind of class-hierarchy would you come up with? There is no single way to do it. Some ways are better than others. There migh be more than one optimal way.

Same goes with generalization general, it is part of the language we create to describe things and there are many different languages we may come up with, some simpler, some more difficult to understand.