Exactly. I was responding to the claim that the price of ads was necessarily correlated only the wealth of buyers. It is on average correlated to the expected return a given company expects to get in terms of products sold / conversions.

So I agree with you. If I advertise to sell something in the US (where I am, where my company does business, where I am willing to ship goods, etc.) then ads in Thailand are worth $0. Not because the people there are poor, but because I don't do business in Thailand.