Ads aren't about reliability. There's a very low cost for exposing someone to an ad that won't generate sales. So as long as exposing a GROUP of people to that ad DOES generate sales, that's going to drive those ads.

That really doesn't address what I said.

"People themselves are one of the least reliable sources you can use to determine what it is they actually want."

I'm not sure the idea that people are bad at predicting what they want makes a lot of sense if there's nothing to show that they're bad at it.