It disappears almost before you get it. And then, you've got to go out and get some more. It is wise to have multiple streams of income flowing into your life. Prosperous people have always known this. If one stream dries up, they have many more to support them.
Ordinary people are much more vulnerable.
If they lose even one of their streams, they're on the streets. It wipes them out. And it takes them years to recover. That's the main reason why they never seem to catch up. If so, that's linear .