> Notice how with their consoles, if the disc/cartridge fits in the console, the console will always play it, even between generations.
Well, that's not quite true. Both the Wii and Wii U have a standard-sized disc slot; on the Wii you can insert small GameCube discs into that slot and they'll play, but on the Wii U they won't. On the portable side, 3DS cartridges do have a tab to prevent them from fitting into a DS, but that wasn't the case for the handful of games exclusive to the brief-lived DSi.
Recent Nintendo consoles have also had compatibility issues with standard storage devices. The Wii supported SD cards, but wasn't compatible with SDHC cards, which are almost all cards with a capacity of 4GB or higher. This was eventually rectified with a software update... but the update only applied to the system menu, not to games which could access SD cards themselves, including notably Super Smash Bros. Brawl. The Wii U, for its part, supports storing games on external hard drives, but doesn't provide as much power over USB as most hosts do, requiring the use of a USB Y cable and a separate USB power source even for drives that don't normally require external power.
Well, that's not quite true. Both the Wii and Wii U have a standard-sized disc slot; on the Wii you can insert small GameCube discs into that slot and they'll play, but on the Wii U they won't. On the portable side, 3DS cartridges do have a tab to prevent them from fitting into a DS, but that wasn't the case for the handful of games exclusive to the brief-lived DSi.
Recent Nintendo consoles have also had compatibility issues with standard storage devices. The Wii supported SD cards, but wasn't compatible with SDHC cards, which are almost all cards with a capacity of 4GB or higher. This was eventually rectified with a software update... but the update only applied to the system menu, not to games which could access SD cards themselves, including notably Super Smash Bros. Brawl. The Wii U, for its part, supports storing games on external hard drives, but doesn't provide as much power over USB as most hosts do, requiring the use of a USB Y cable and a separate USB power source even for drives that don't normally require external power.