What did he test though? That over a given decade, unemployment might be higher in one nation-state than a collection of others?

What's the hypothesis? Where's the valuable data gotten from this?

My idea of equivalent action: Me stating "the president 10 years from now will be the first 3rd party president ever."

Why? Who knows! And if I was right, and make a blog post that says "See, I was right!" And then point to a bunch of things that happened after my prediction that led to this result, what did we learn? Anything at all?