Variation does not equal distinction. You can have millions of gradients around white letters which will not be perceived by anyone as distinctive. On the other hand you can have black letters arranged in a million ways that will look distinctive. It's all a subjective selection.

There is an infinite number of ways to design a black logo. There is an infinite number of ways to design a blue logo. So which infinity has more distinctive logos?

Not all infinites are the same size, but that’s irrelevant as there are only a finite number of perceivably distinct logos.

Anyway, for any distinct set of black logos you can map them to a larger set of blue gradient labels therefore the number of distinct blue logos with gradients is larger.