Everything in the economy is cyclical. Nothing great or terrible is likely to stay that way for long, because the same forces that cause things to be great or terrible also plant the seeds to push them the other way.
Bull markets make stocks expensive, expensive stocks leave little room for error, and little room for error increases the odds of bull markets ending. Same thing in the other direction. Recessions cause pessimism. Pessimism causes underproduction, underproduction leads to scarcity, scarcity leads to a new boom.
Getting rich can be the biggest impediment to staying rich.
It goes like this. The more successful you are at something, the more convinced you become that you’re doing it right. The more convinced you are that you’re doing it right, the less open you are to change. The less open you are to change, the more likely you are to tripping in a world that changes all the time.
There are a million ways to get rich. But there’s only one way to stay rich: Humility, often to the point of paranoia. The irony is that few things squash humility like getting rich in the first place.