I'm going to stop going back and forth on this. But let me just say this: verifying paid traffic, within the ad platforms as well as on your website is totally possible.

If you want to second guess the psychology of whether or not the ad "drove" the user to make a purchase or not, that is up for discussion. Or whether Google/META do shady shit in their bidding environment. Absolutely.

But this idea that you can't track everything is bullshit.