I'm afraid that this is a case of someone imagining that there are Platonic ideal concepts that don't evolve over time, that programs are perfectible. But people are not immortal and everything is always changing.

I almost burst out in laughter when the article argued that you should reuse types in preference to inlining definitions. If you've ever felt the pain of needing to split something up, you would not be so eager to reuse. In a codebase with a single process, it's pretty trivial to refactor to split things apart; you can make one CL and be done. In a system with persistence and distribution, it's a lot more awkward.

That whole meaning of data vs representation thing. There's fundamentally a truth in the correspondence. As a program evolves, its understanding of its domain increases, and the fidelity of its internal representations increase too, by becoming more specific, more differentiated, more nuanced. But the old data doesn't go away. You don't get to fill in detail for data that was gathered in older times. Sometimes, the referents don't even exist any more. Everything is optional; what was one field may become two fields in the future, with split responsibilities, increased fidelity to the domain.