also one should always be skeptical about the extent they believe they are not influenced by ads. that runs pretty deep. you say you instinctively don't trust it. but when the time comes to buy something, you won't automatically steer yourself towards a product that you have never heard before just because you have not seen an ad for it. having some names in your mind, even them showing up when you do research creates influence.
Now, huge companies do run focus groups and such to ensure their brand advertising has the right (psychological) effects. But it is inherently difficult to measure. And I've seen many mid-sized companies not do that at all, they run these ads based on what they believe might work.
Mind you, this is experience from 4 years ago, but I did find the ad industry, as obsessed with tracking as it is, to be surprisingly gut-driven. For a lot of it, it's hard to tell if it works.
I do fully agree that for people who know what they're doing, advertising absolutely works, in ways that are sometimes unintuitive to consumers.
Top of funnel advertising is definitely conversion oriented, just on a longer timescale.