* Hair density varies greatly: The number of hair follicles per square inch on a person's scalp can be quite different, regardless of hair color.
* Hair thickness varies: The diameter of individual hairs also varies, meaning a person with less dense hair might have thicker strands, potentially resulting in more hair volume overall.
* Hair length and style: Ultimately, the perceived amount of hair is influenced by how long it is and how it's styled.
In short, hair density, thickness, and style all play a larger role than hair color in determining how much hair someone has.