One of my previous employers (international mega company) spent millions on advertisements each month, with no clear way to measure their direct impact. But they did it for the impressions.
From https://thecorrespondent.com/100/the-new-dot-com-bubble-is-h...
There is the issue. "I." You may be one in 100,000. Also there is a trickle-down effect. A brand will spend enough dollars to attract a certain number of fans, then those fans attract others organically. Many will say you "Ads do not work on me," but unless you know exactly why you choose product X or Y, it is difficult to say with confidence.
I'm stunned when I see it but I agree that the average person is heavily influenced by advertisement. Influencers and ads can implant ideas in the minds of people that they replicate with absolute naturalness without thinking about it ever. Like: "X is the best Y". Which reminds me of Venus Inc.
As a consumer I spend more time than I should thinking about what I buy. I'm heavily influenced by reviews and opinions which I know to be biased and not always authentic but is still the best way to discover hidden issues in a product. I frequently think about the characteristics that I like to see in the product and compare it with similar products. But sincerely, trying to approach a rational decision has become time costly if not counter-productive due to lack of reliable information and strong noise. Pay and pray might be a better strategy.