It’s kinda hindsight, but I remember noticing the general decline of thought in Americans ever since I was in high school. It wasn’t until recent decades that I could really sense the connection of that decline to the full machinations of collective advertising methodologies. When reading old works and letters from pre-1930 Americans, it is unfathomable (who talks like that?) That it’s the same country.
There’s some skewing because few letters are saved from the common folk, but advertising has now made everyone celebrate uselessness and stupidity as “intellectual property” and “art.” It doesn’t help that professionals have embraced the same styles as if idiots are the greatest new way to educate children.