A possible clue is that the weird composed form is, still, the only possible form in which you can actually get results out of your SQL database.

Perhaps people worked backwards from sample query results, reasoning that an output that looks like that should come from a table that looks like that. Of course that begs the question of why that ever seemed like a sensible format for output, but apparently the SQL establishment has never seen fit to change it, so either the SQL people are all idiots or there's some advantage to that form.

(Yes, I know there is an obsolete meaning of that phrase still recorded in some dictionaries, but I prefer to use live English)