Unless you are Kishimoto-sensei, you can't say with that amount of certainty that Sasuke won't catch up to Naruto. Your title implies that this is set in stone, which it obviously isn't.
Kishimoto-sensei himself has stated that the two are like yin and yang, and that when giving a power up to one, he always keeps the other one in mind for a power up as well. Also throughout the whole story it has been repeatedly shown that one time Sasuke is at the advantage and the next it's Naruto.
Currently it's Naruto, but it's obvious that in the end they'll be equal, because otherwise that would defeat the purpose of them having a possible fight or their bond in general