A new meaning to the saying, "A Penny Saved, is a Penny Earned"

Holly Ordway is only 30 years old, yet she is already financially well on her way. By learning to spend money only when absolutely needed, getting by with just the minimum, and watching for sales and great bargains, Holly and her husband are living off of thirty thousand dollars a year, yet they have six-figures in the bank. "Being frugal is all about making good choices with your money," she said. "It is important to understand how you are spending your money and to know that you are spending it in ways that match your goals." Holly claims that she does not have a strategy, she just spends only what she absolutely needs and saves the rest.
Obviously this "strategy" seems to be effective if Holly and her husband are able to get by on thirty thousand dollars, and yet have so much money in the bank. What would happen if everyone tried to spend as little money as possible, and invest the rest in savings? How would that effect the economy?