To be able to reach this conclusion you need a minimum level of travel to be able to get knowledge of a lot of languages. Just knowing two or three isn't enough. You probably need at least some knowledge of a dozen or two before you can start seeing links. Preferably you have access to older versions of languages. You can see the links more by comparing Old English to Old German than you can with the modern languages. You also need the ability to distribute information so many people can see copies of it - that means you need printing presses. It probably wasn't until the 18th century that anyone could put the necessary parts together and it was Western Europe that was on top at the time.
Great post.
An excellent and informative post. Thank you very much.