Metroid really illustrates Nintendo's cultural myopia - to a degree. The series was never popular at all in Japan, so that was a strike against it right there. I'm pretty sure that Other M was meant to appeal to Japanese gamer sensibilities, but that didn't work, either, the game sold worse there than here. The game mechanics were honestly the most troublesome part of that game for me, since I didn't have a lot invested in Samus as a character. And I always wanted a third-person Metroid. Even the Prime games, though I enjoyed the first and third games, were lacking some of the Metroid magic for me because a lot of Metroid's signature power ups didn't really work with Prime's mechanics.
However, to be somewhat fair to Nintendo, regardless of their half-assed handling of what is considered one of their signature series, even in the US it never sold anywhere close to the level of Zelda, Mario, Pokemon, or even a few of the "lesser" Nintendo properties, particularly given the resources Nintendo sank into it when they did decide to give it a go. I think Super Metroid managed to crawl past just over a million units, which was probably eclipsed by Donkey Kong Country within a couple of weeks.That Nintendo invested in Metroid Prime at all, let alone to the degree it did, was more than anyone could have hoped for, though Nintendo also needed some killer content for the Gamecube which was another impetus behind Prime.
