Novelty; i think you have to agree that the service of Hashem is different for goyim than it is for Jews. We have 613 mitzvos, and they have 7.
They are also incapable of sanctifying the physical world, which is why the only korban they can bring is an Olah, which is completely consumed on the mizbayach.
Shimon, why am i wrong? I think it’s a very good cheshbon – bechira is to do what’s right and wrong, and goyim have less opportunity and capacity for those decisions, therefore they have less bechira.