I work with user data in Search and this is a common sentiment ... but I think it slightly misstates the purpose of using user data.

The primary purpose has always been improving search overall -- traditionally this has meant updating query interpretation, ranking, presentation, etc for smaller and smaller query slices ("Ah, when we show the mayor and the population in response to [Barcelona] people just revise their query to [Barcelona FC], so we should make sure to include latest match result on the top. Not so for [New York]."), and running tests on every product change to see what people like. In this case nobody cares about any _individual_ user's data, only the collective. This is basically the original "collective intelligence" contract of PageRank, albeit hillclimbing on billions of searches and clicks instead of using link structure. (Old question: does original PageRank count as machine learning, or not?)

Second is personalization -- things like "Oh, my flight or my delivery is expected on date X, handy that gmail popped a reminder on my calendar, good work Google." Or searching for a restaurant in Maps and seeing results that are biased towards the kinds of restaurants you already like, that kind of thing.

When it comes to revenue the purpose of these isn't to target ads, it's just to have you get value from and use the product, and when you are ready to spend money this is where you come to search for the thing, whatever it is.

Finally there is limited use of a limited set of data for ads relevance. There's higher CPC for ads you might actually be interested in (and if you are looking to spend money, is finding a willing seller who has compelling terms via an ad such a bad thing?) But ad revenue is mostly downstream of users being satisfied with the core product and using it more, whatever that product is. (Search, Maps, AI chat, etc)

(Bonus. My Search pro tip re: ads is leverage the modern stack and spell out your intent with a few more words when you query. We're pretty good at not serving ads for non-commercial queries. But old-school super short "searchese" queries make it hard to guess whether your intent is commercial or not.)