Super Mario 64 was so legendary at the time.
Basically every platformer after SM64 superficially copied it. Most platformers dropped you off in a hub, unlocked the first world and said "get 6 (completiion items) to unlock the next world." Just like SM64. The big difference, of course, is that SM64 did it already.
For more fun, let's rewind to the NES era. Super Mario Brothers spawned a million platformer clones where you ran from left to right, jumped over pits, dealt with enemies in some way and cleared multiple stages. Some of them had variants, like giving you a melee attack or a gun or a strict timer, but they were all following SMB's blueprint. Sega eventually broke out of that by making a platformer that was fast and had "attitude." Thus Sonic the Hedgehog.
Look at the XBox & XBox 360. Lots and lots and lots of FPS clones. Most of them with "take cover to regain shield" mechanics. Just like Halo. Sure there are variants (2-player online coop, different weapons, different plots) but they are following Halo's blueprint to the letter. Has a break-through FPS emerged yet? I don't really know (a little help from FPS nuts out there?)
So when the Wii came out, what did developers see? Wii Sports (OMG TECH DEMO?) Rayman Raving Rabbids (OMG MINIGAMEZ!) and promptly shoved waggle-driven tech demos onto the Wii. Of course, they didn't notice how Nintendo used its A teams to program Wii Sports or how subtle the controls are in RRR. But they'll figure it out soon.
There is no such thing as a console war. This is the first step to game design.
