Motoo Kimura, the evolutionary biologist who developed the neutral theory of gene mutation, showed that you don't need selective advantage to become pervasive. Some neutral genes increase in frequency to become universal, some neutral genes are just extinguished. It's just a demographic phenomenon.

Also, 10,000 years is a pretty long time (500 generations-ish). Think of the potential number of offspring in that time -- Starting with one couple, assuming each generation averaged 2 kids per generation, that's 2 to the power of 500 more people than are on the planet (by a lot). Not to diminish they're importance, but there really aren't that many people with blue eyes.

Last note, be careful about using words like dominance in this context, since it's a term of art.