TP - We can all speculate on the real reasons for the apparent "downfall" and certainly fiduciary responsibility is a major motivating factor in most decisions to change. That being said, I like to explore the lessons the game teaches us to try to decipher the "why".
Ego, after kicking deutchlands proverbial ass, and saving Europe and other areas, America had what is commonly known as a swelled head. Justifiably so, they had proven their metal to not only themselves but to the rest of the world.
One possible "reason" is that egos, had swelled to the point of where accomplishments, were a given. The toxicating understanding that "we" could do anything we put our minds and muscle to, had to become the projected attitude, especially from those with the wealth to live ultra-comfortably. And what happens in this game, when we get to the point where we think 'we are good'? I no my own experiences have taught me that that is not a place where good things happen
This arrogance transfered to gca and the egos of those in power to affect change. Albeit, in hindsight, poor changes. But it would apper that your example of the elderly gentleman who admitted,"they had no idea", supports the theory of arrogance and proceeding without doing the research.
I'm surprised Pat hasn't more constructive information, since he admitted that he and his Dad were integral to the high social & golf scene, back in the day.
So, in conclusion, indirectly, it's all Mucci's fault.