The US is not in a steady downward spiral. Some years things improve and others they get worse, but it’s individuals that make the decisions shaping history.
Of course USA is not in a downward anything. USA government on the other hand is certainly circling the bowl. There is a difference between those! It may be that various states of America will eventually decide on a different way of organizing society. I'm hopeful, because when things change they often get better.
It's curious that you can see how incentives shape the behavior of some people, but not that of other people.
I am specifically saying the US government has been more and less corrupt in the past.
It’s not about people at the top responding differently it’s about the flow of influence. If 20% of the people at the bottom behave poorly the other people at the bottom have little influence. That changes at the top as it’s easyer to monitor a small group of people and their actions are more documented.
Ex: A cashier can fail to scan items for their friends at checkout and without any form of paper trail. The CFO can do more harm, but it’s harder for them to act in secret.
