Why are the textbooks always about foreign students coming to Japan and experiencing Japan?

I've only ever worked in JHS as an ALT. So what it's like elsewhere I don't know.

But the stories of the textbook always bothered me. Wouldn't it make more sense for the Japanese characters to leave Japan and experience a native English country?

You know instead of just explaining Japanese things in English to the foreign student characters or the female ALT character. But I guess that wouldn't satisfy the Japan is amazing and unique circlejerk.