Why not consolidate the pages? Because of the nature of hypertext. The virtue of hypertext is links. That means that you can have pages that serve as a hub for further discussion, with links to them. Now, someone who knows what the opening is may have little use for a page that simply says what it is and what terms are used for it and a brief description of it. Like looking up a word you already know in a dictionary. By comparison, "About the Opening" is like an encyclopedia entry, with a fuller discussion.

Sometimes in this Wiki you can see the opposite, where a definitional page, which could have only a paragraph or two, ends up with a full discussion, including different points of view. Someone who just wants to find out about the concept can easily get lost in all of that.