I'm still not hearing a good reason to learn another language. Just that in your opinion it's arrogant not to. OK, if I want to understand an Italian song, I better know Italian, read a French poem, I better know French. Even if I knew 8 languages, there would still be a 9th piece of literature that I couldn't appreciate in its original tongue. So I'd still have that same problem.
But, the international people are not learning English just because they are interested to know what Nickelback's latest song is about. Is it just a random accident that English is the dominant language in the world? If it is just a random accident, then I probably would have learned whatever secondary language had turned out to be the dominant language of the world. I don't think I would have (just because I'm an arrogant American) refused to learn another language if I could point directly to some marked benefits for doing so. And even if I'm wrong about that, and I would have actually refused to learn the dominant language of the world, that's not the reality of the situation. These people have given us a lot of sound reasons as to why they learned English. I'm still waiting for an equally strong list of reasons to learn another language. All I'm hearing is it's arrogant not to.