I wanted to stick with the language side this that is what the original article was about. But yes, in large games you wouldn't do all that stuff in C#/C++/etc, you'll most likely use a data driven approach. However this can still be put at the gameplay side of the engine to provide the base. For example if you look at the mod tools for RPG engines like Aurora, Creation Kit and REDEngine you'll see that they have inherent knowledge about base item types like armor, monster, etc, but they rely on data for the specific items (and scripts for the exceptional behavior). The easiest to see that is with the Creation Kit based games like Skyrim since it gives you a nice GUI to create/edit each different item type.