Kind of an odd topic since it seems a little concentrated on our particular demographic but okay
It was more succesful in Japan for a few reasons. Marketing was much stronger there. Sega used better and more expensive marketing tecniques in Japan and it was just distirbuted on a grander scale in terms of paraphnalia and advertising.
They also released more games in Japan because they thought the games would be lost on us. This is probably true, but a good handful of games such as radiant silvergun for example, would have sold insnaley well here (this being depandant on if the marketing was better here in the first place). The culutreal aspect also came into mind. America wouldn't stand for a bunch of those hentai games that seem oh so common in Japan. With the time and money it would take to translate those types of games, it would reallyb e more of a loss to sega.
You say the saturn, after being brought here was not succesful, but this is not true. While not as successful as the playstation, it was still more or less a success. Again though, the reason it did better in japan is because of what is stated above.
And becauase of the wording on that last part I Really dont get what you mean