When you have historical data about customers, you have the key to understanding their future behavior. Because people are creatures of habit with predictable life patterns. The habits that we form early in our life stick with us throughout our life. The clothes we wear, the place we live, the food we eat, the cars we drive, how we pay our bills, how we invest, where we go on vacation - all of these features are set early in our adulthood. Understanding a customer's past history then becomes a tremendous predictor of the future.
Customers are subject to patterns.
In our youth, most of us don't have much money to invest. But as we get older, we have more disposable income. At mid-life, our children start looking for colleges. At late mid-life, we start thinking about retirement. In short, there are predictable patterns of behavior that practically everyone experiences.