The god of the gaps is used to fill the last gap in front of a fundamental explanation of the physical world.
Fundamental physical constants, like the masses of the elementary particle families (or their coupling strengths to the Higgs field) and the coupling constants of the fundamental interactions, cannot be explained by the standard model. String theory states that coupling constants and masses are randomly distributed over a huge landscape of possible solutions to the overarching theory.
There are different theories to explain the physical constants. This renders a god of the gaps, who sets the constants in order to make life possible, superfluous.
How are the theories themselves explained? If there is no gap left, it seems that there is logically nothing else to conclude that God created the universe, even when it's eternal.