You're right that the simile starts falling apart when you look at it deeper, but on the whole I think it does provide a reasonable example: when you can experience international travel and business opportunities in your mother tongue it is less appealing and more difficult to learn another language. And this is what we see from French-speakers vs Finnish-speakers. Yes, French is much more global than Japanese is, but the end result is the same: if you speak French or Japanese, there are many more economic, cultural, and travel opportunities available without needing to learn a L2 than if you speak Finnish or Dutch or Hungarian. That's part of speaking a language with 100+ million speakers compared to 5 million speakers.