I have many friends who have worked in Search in the last decade. You seem to be interpreting "incentives and culture" as "explicit directives or pressure from

I have many friends who have worked in Search in the last decade. You seem to be interpreting "incentives and culture" as "explicit directives or pressure from Ads". There are many ways for culture to grow. Chinese walls can prevent many overt pathways from growing, but they aren't an antidote to the overall role incentives play inside companies.