Planned by TTC maybe. But for Nintendo's own franchises, it might be longer, as long as retailers continue to sell enough copies to justify giving it shelf space. Nintendo could always press another run of discs or burn another run of Game Cards if a game continues to sell. Case in point: Animal Crossing: Wild World is still on shelves after slightly more than two years. Super Smash Bros. Melee was in print throughout the GameCube's five-year commercial life. The difference with Tetris DS was that it was taken out of print while sales were still noticeable, driving up the used price. Even now, on eBay, some copies are still selling for more than the price of what you need to run KGM or Lockjaw.
