Is the 80-20 rule universal?

Is the 80-20 rule universal?

This “universal truth” about the imbalance of inputs and outputs is what became known as the Pareto principle, or the 80/20 rule. While it doesn't always come to be an exact 80/20 ratio, this imbalance is often seen in various business cases: 20% of the sales reps generate 80% of total sales.