But where is the evidence that it actually performs as advertised? Does it make software easier to deal with? Is it superior to alternative ways to achieve that

But where is the evidence that it actually performs as advertised? Does it make software easier to deal with? Is it superior to alternative ways to achieve that? What are those alternative ways to make a huge system manageable you allude to? As I said, none of the paradigms put forward as alternatives even claim to operate like this. It's serious question, what are the alternatives in this kind of situation? And I'll admit, a "horrible messy situation" that we'd look at today is going to be an earlier OOP system.