What is the state of the non-tech part of the advertising industry

Unless you have employee-level access, I wouldn't trust anything people are saying about the psychology of advertising. The reality is that people tell lots of stories about why things happen, but they only have the power to say that something happened.

The search for "why" is both very human and a big problem in terms of explanatory power. That is to say, someone has a finding and publishes it. That may (or may not!) be relevant to the specific tight scope around the survey/research. However, be very, very, very cautious in generalizing - that's where most people in ads/conversion optimization go wrong.

The psychology of persuasion was pretty much solidified by the early 1900’s, through the use of direct response advertising.

Back then, it took weeks to figure out which ad copy had better ROI. Now you can do huge tests and figure things out in minutes.

I don’t think there’s been any huge breakthroughs in a long time. All marketing/advertising is just recycled and presented in slightly different ways