Well, IR pointers weren't a big deal before, and now they are. The reason the Wii is the only system to have one is because Nintendo were the only people who decided to take something so small and so cheap and so simple that nobody else is using and nobody else cares about, and use it so well in both games and the system interface that it becomes a big deal. You just point and click, like a TV. Anybody can do it, and it replaces a whole clunky analog stick on a traditional controller.
Now we get everything from Elebits to Metroid Prime 3 to the Conduit as Wii exclusives, because they rely on IR pointing.
Sony and MS were busy focusing on really big really expensive really powerful ideas, and their business model doesn't really allow for R&D on a tiny piece of plastic that costs a buck to make that you put on your TV. However, it makes games more fun and immersive, and everybody but Nintendo missed the boat. Why? Because Nintendo built the boat when nobody else was looking.
(You can continue this metaphor if you like by discussing the giant blue oceans this boat is sailing on while the coastal cities back home are slowly sinking.)












