But marketing to a higher income demographic is considerably more expensive (per eyeball/impression). High income demographics are targeted with ads for high-ma

But marketing to a higher income demographic is considerably more expensive (per eyeball/impression). High income demographics are targeted with ads for high-margin goods (cars, vacations, fashion goods), which have 3- to 5- digit margins that can be used to advertise them, so there is more competition to target ads towards wealthier people.