That's a very misleading way of putting it. From your own article:
> In addition, Google does not know what products people bought.
Of course not. Whose credit card statement includes a listing of the individual items you purchased at a store during a particular transaction?
It's not in the statements that you received, it's a reciprocity agreement between retailers and CC companies to share the data by CC #
For example, CC companies could give you your itemized purchase history for Macy's on your statement, if they wanted to.
Re:DuckDuckGo will use Apple Maps
by londons_explore on Wednesday January 16, 2019 @02:21AM
(#18918895)
It is my understanding that most stores do not share that data, because they feel it is a significant commercial advantage.
Credit card companies have wanted itemized transactions for aaages (it's even part of the protocols they use) for fraud prevention, but very few merchants have agreed.
>Google has been able to track your location using Google Maps for a long time. Since 2014, it has used that information to provide advertisers with information on how often people visit their stores. But store visits aren’t purchases, so, as Google said in a blog post on its new service for marketers, it has partnered with “third parties” that give them access to 70 percent of all credit and debit card purchases.
https://www.technologyreview.com/s/607938/google-now-tracks-...
Perhaps other search engines will reach this extreme level of creepy behavior in the future, but Google is there today.