Ah, yes, I did misunderstand, my sincere apologies.
Kojima is not a businessman; he is an auteur. "Mindshare" may be nebulous and immeasurable, but it is still very real, and he's watching consumer tastes slowly move away from Japanese games. His concern is probably more of a cultural one than a financial one. Does it make sense? No, not if you're a business - but Kojima considers himself an artist first, with everything that that self-distinction implies.
And, again, I don't think he's counting Nintendo.