Spoiler: USA has changed from being exceptional in a good way to being exceptional in a bad way. The dynamism of US product markets has decreased. It shows up in lower firm growth, higher concentration and weaker competition. This has led to increased inequality, lower investments, innovation, and productivity growth. At the same time, horrible things are happening with parts of the population. Life expectancy rates are declining because people are dying from suicide and drug abuse. Since this is happening mainly to people with low education and incomes, inequality in health is increasing.
To reverse the developments, the political system needs to be more transparent and less sensitive to rent seeking by large enterprises. But unless the Trumpian tendency to autocracy is reversed, it will be difficult to make the necessary changes.