Ok, so who in the real world would learn whose language? Could French hire Kaluli interpreter who speaks French, or could French hire a French interpreter who speaks Bosavi? All I'm saying, in the real world, both things happen depending on the availability.
What's targeting the local population is the non-speaking handicraft, but there's the whole marketing requiring lots of speaking and knowing the culture of the target audience. Again, it could do either way, a Kaluli firm could hire a Kaluli who's fluent in French to act abroad, or alternatively, the Kaluli firm could hire a French agent who's fluent in Bosavi. That depends on the availability of the resources. All, I'm saying, the economic ties would inevitably cause mutual language and culture studies. The tighter the ties, the more language studies. If all of a sudden it becomes fashionable for the French tourists to come and visit Papuan Plateau, whoever of Kaluli speaks better French, would get more money as they could provide more hospitable environment. And if French tourists would know Bosavi language better, they would find more exciting experiences. And so on.
I'm not sure what makes you so irritated about point 1, isn't that the natural process that had happen everywhere?