After I make my decision and buy one (online, or in person), I no longer search for "vacuum cleaner reviews", but I search instead for "skiing in January" and I no longer get adverts for vacuum cleaners, I get it for ski resorts.
Odd take IMO that Google's ever encroaching ads make their product better. Heck, Larry and Sergei even wrote a treatise (it used to be available directly off google.com, can't remember the name) about how they would be different from search engines at the time, how they wouldn't sell search position, and how the ads model was fundamentally at odds with end user experience. That's hilarious now as Google has gone to great lengths to make ads as indistinguishable as possible from normal search results, and for some terms my entire front page is ads. Compare that to "early" Google where ads were clearly identified in top and right sections with a yellow banner.
Hey! You just bought a filter for your air purifier! Want to buy a new one! For a different purifier you don't own!
No, talk to me in six months.