Why did the rich man go broke?

This joke plays on a clever bit of wordplay and a touch of ironic absurdity. The phrase "going out of style" is typically used to describe fashion or trends that are becoming outdated, like bell bottoms or flip phones. The humor comes from applying this concept to something as fundamental and enduring as money. Money doesn't literally go out of style; it's always useful, always current. The punchline twists this idiom, suggesting the rich man was spending as if money itself was a fleeting trend that would soon be worthless, leading to his financial downfall.

The underlying humor also taps into the common understanding of extravagant spending. To "spend money like it's going out of style" is an idiom meaning to spend lavishly and excessively, often without regard for the cost or future implications. It's a relatable exaggeration of someone who simply can't control their spending habits, even if they start with an immense fortune. The irony is that by treating money as if it were a temporary fad, the rich man ironically made his own money temporary, leading to the very real consequence of going broke.