If blue eyes are a recessive gene and green eyes are a dominant gene, why are there more people with blue eyes?
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Worldwide there are more people with brown eyes than blue eyes; this is true in the United States too. https://www.healthline.com/health/eye-health/eye-color-percentages
The commonness of an allele isn’t determined by it’s dominant or recessive nature. The commonness of an allele depends on how much that allele promotes the survival and reproduction of the individual with the allele in a specific environment. Here brown eyes, associated with melanin production, is the result of selection for survival in environments with intense sunlight in the absence of clothing to protect skin and its cells from UV light. UV light can cause mutation in skin cells, one outcome of mutation is the formation skin cancers.
The frequency of skin cancer does depend on racial ancestry with caucasians having the least skin melanin and the most skin cancer. Similarly individuals having negro ancestry have more skin melanin and the lowest incidence of skin cancer. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2757062/
If we accept the African evolution of humans, and the out of Africa migration of humans, then our ancestors were brown eyed. It is as humans migrated into latitudes with less sun intensity that there was less selective pressure for melanin production, that non-brown eye colors become apparent.
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