Prestige as viewed by students or professors doesn't match funding provided by NIH, which focuses on diseases that affect Americans, both by mandate and because of lobbying by individuals. Other sources of funding are drug companies that don't have much opportunity to sell to poor people, and disease-specific charities, established by rich people because of relatives who have the diseases of rich people.

Or maybe it has nothing to do with prestige, but the perk of a field trip.