The problem
In order to stay in business, the typical for-profit company must meet its consumer demand with an adequate supply of valuable services or products. The primary role of the ScrumMaster is to bring visibility to the development team's true capacity, so that the organization may balance that against its consumer demands. Unlike a manufacturing line in which the management measures units delivered per day, Agile software development is measured in terms of customer happiness based on the features or feature set delivered by the team. In this day of viral YouTube videos, tweets, and other such media, companies must stay focused on delivering today's most important demands quickly, while maintaining a flexible response to rapidly changing competitive and consumer landscapes.
A few decades ago, the waterfall response was, in fact, adequate because new markets weren't being created every day, the Internet did not exist as we know it today, and it took much longer for people to spread their messages and ideas around the world. The viral Gangnam Style or recent Harlem Shake are testaments to just how quickly words (and funky dances) can travel. There is simply no time to play around these days.
I've attempted to illustrate the opposing forces of supply and demand in the figure above. The business continuously demands new features and products from the technical team, whether it's the CEO with a new mandate or a product manager in need of a cool new feature. A professional ScrumMaster can help the business see when the balance is tipped too far in one direction; and most importantly how to best use its capacity to respond to demand with speed and quality. There is no perfect long-term solution; rather the ScrumMaster must help the organization find balance as the landscape on both sides constantly changes.