I think it was always a bit like this. You can read what people thought about advertising in the 60's, and they had the same kind of paranoid fantasies we have today, although less focused on tech, more on psychology. In reality, advertising psychology then was much as it is now - basically quackery, with a side of 'thought leadership' by guys that really should have stuck to squash.

That said, I think the reason why machine-driven advertising is so much better than its predecessors is simply that the predecessors were really awful. They used to do market research by installing double-sided mirrors in department stores then taking notes on what people looked at. It was absurd. Now, there's actually an even-odds chance that a targeted advert will meet somebody that might be vaguely interested - and that's absolutely orders of magnitude better than a billboard.

And also, to be honest, this whole complaint about cost-performance indices is a bit absurd - since as far as I can gather, they were basically oneiromancy before Google and Facebook came along.