I think that in the context of learning foreign languages, you have to distinguish between the willingness to learn about "cultures" and the willingness to gain information unavailable in your mother language. You can still gain some pretty detailed information about the French revolution in English, and only if you wish to specialise closely on that subject, you'll probably need fluency in French. Conversely, you can learn a lot about Victorian England in French. I'm trying to illustrate the fact that important and valuable information is not necessarily siloed by language.

English is the defacto international language nowadays. I am Bulgarian, and after crossing the border with neighbouring Romania I'm using English, since the effort to learn Romanian is not worth the time when my intentions are just to travel there occasionally. The two languages are very different, and Romanians aren't willing to learn Bulgarian either.