Plus Rosalina can always just reboot the universe and create a fresh planet with a fresh layout anytime the devs wantThe way Mario is conceptualized it's best not to take geography so seriously. This planet was created for this game and its geography takes into account what matters for this game. If it's on this map then it's probably a place you go to, and future games will likely pay no heed to this map. As a cartooby video game Mario lacks real-world limitations in creating the stages the plays are performed on.