There doesn't have to be any malicious intent, just an endless chase for increased profit next quarter. SEO spam has more ads, thus generates more income for Google. Even if Ads and Search operate "completely independently", there must be a person in the corporate hierarchy which has control over both and could push the products to better synergize and make that KPI tick up.
Actually deranking sites which feature more than three Google Ads banners would improve search quality (mainly by making sites get to the point rather than padding a simple answer into an essay like an 8th grader at an exam) - but it would reduce Ads income so you cannot do it, no matter how independent you claim to be.
There doesn't have to be any malicious intent, just an endless chase for increased profit next quarter. SEO spam has more ads, thus generates more income for Google. Even if Ads and Search operate "completely independently", there must be a person in the corporate hierarchy which has control over both and could push the products to better synergize and make that KPI tick up.
Actually deranking sites which feature more than three Google Ads banners would improve search quality (mainly by making sites get to the point rather than padding a simple answer into an essay like an 8th grader at an exam) - but it would reduce Ads income so you cannot do it, no matter how independent you claim to be.