Earlier quoted context omitted.
How do you propose you track ad spend without "spyware"? Or should the people spending money on ads just "trust" that their ads are actually being displayed to the types of people they want to show them to?
The same way ads work in every other industry. Have you ever been to Times Square?
So you want a regression, why exactly? If you don’t want to be tracked stop using sites that track you and install ad block.