Eso sería parte de un buen argumento, que los humanos se han extinguido y llega Olimar, extraterrestre del planeta Hocotate y etc ....
EDITO:
De hecho algo así parece que ya existe en el tercer DLC:
The third pack of DLC, and possibly the last, was released during the holiday season. It cost £4.79 | $4.99 | €4.99. It featured stages that were (mostly) not in nature, but rather was based on objects made by man. For example, some stages were an abandoned construction site, a living room decorated for Christmas, and a factory. One stage, Forgotten Cove, is actually a reskin of The Forest Navel, most likely due to the fact that it did not appear as part of another stage in Pikmin 2. The Fortress of Festivity stage is available for free upon updating the game.
Creo que voy a cogerme los DLC´s