Because the fastest and easiest way to make the line go up is to cut costs, and the fastest ways to cut costs are to cut corners on your product, or cut your staff. Both of these action only produce a brief “line go up” moment before their consequences cause line to go back down. But you’re a line go up guy, and you know just what to do, cut more corner! Reduce more overhead! The problem is that eventually you won’t be able to cut anymore corners, or reduce any more overhead, and then the whole house of cards comes tumbling down.