When it becomes more profitable to teach people how to do something than it is to do that same thing for customers then it is game over.
That is what you wrote. I wonder if you realize how correct (in a way you may not have meant) this is. I am 76 and while you may have ridden the wave of advertising photography I was involved in magazine photography/writing and annual reports. And because I live in Vancouver those annual reports involved hefty day rates to photograph logging mills on the ground and from the air.
Now I see that my former editors are all teaching journalism at universities and technical schools. Where will the graduates go? There are a few media “universities” in Vancouver where wealthy students from abroad are taught photography. What will they do when they graduate?
So you are absolutely right. For former editors who used to be well paid now they profit by teaching something that is gone.
As I see it (and I like the expression that I am obsolete, redundant & retired) it was the death of journalism that did it. In the 20th century magazines and newspapers competed to publish the best and original photographs. I was sent all over the world to get those pictures. With newspapers in quick demise there is nothing left for the photographer.
And where are the replacements for the Helmut Newtons, Bert Sterns and others? I would say that you can also add to your list the death of style.