it's one of the prime examples of bullshit jobs

Always good to see another Hexbear who used to be in Advertising.

but are more likely to just run across it when doing a search for [general type of thing] later anyways

This is not organic. It's called re-marketing. You are running across that stuff later because the ad agencies keep a profile on you and know you came into contact with this ad earlier but did not convert into a sale. They know that re-marketing to you at another more appropriate time can convert into a sale.

The advertisers are selling a dashboard that the marketing department can use to razzle dazzle the higher ups

And then you have the insidious social media influencer shit, especially on Instagram and TikTok, where people posing as everyday randos start gushing about how great X product is... A week later, my partner is demanding whatever the latest Ninja kitchen gadget is, while the last four sit on the counter in varying states of disuse. Or worse, those emery cloth abrasive "hair removers" that are just white label AliExpress trash that scratch the ever-loving shit out of your skin and sometimes leave bits of grit in stuck in your skin and/or pores. It's a little horrifying to watch "consumer demand" get generated in real-time against an otherwise rational person.

Maybe I'm just hyper-aware of it because of my own history with piss-poor impulse control and some hard-learned lessons.

Actually Instagram ads are pretty effective. Because it looks at posts you look, microphone data, messages you send in their dms, and maybe Google account data if you linked it to your Google account if you use those.