Advertising is less conspicuous today.

...Because it's trickery is everywhere. In '69 it wasn't, though it sure as hell was trying. Which accounts for a lot of the disgust for it in this movie.
But the young sprouts of today grew up marinated in the stuff (advertising, not disgust), and take it completely for granted. Which is why they may find PS a little bewildering; it's not just racial/political satire.