Yeah, let's not kid ourselves: the Rainfall games would not be huge sellers on par with something like Mario Kart Wii, but they could probably sell 50,000 - 100,000 copies easily with minimal marketing (as if Nintendo of America knows how to do anything else for core-oriented titles). Assuming that Nintendo of America got a clue and kept the localizations as they were in Europe, costs could be kept to pretty much replication; distribution; and viral marketing. Unless we had the second coming of Demon's Souls, the titles wouldn't be mega-hits, but they'd probably do respectively and turn Nintendo a small profit. Nintendo doesn't get a pass on "not wanting to sell niche titles" when small companies like Atlus and Nippon-Ichi USA have turned that into an art form.
And at this point, is Nintendo really in a position to be picky about how it gets money after posting their first annual net loss since the 1980s?