<p>Why isn't this the case, just make them rolling with an early deadline?</p>
<p>Uh, because the colleges involved want to do it the way they have it?</p>
<p>Rolling admissions entails a relatively quick decision. Some one applies; if they meet the standards of the school they are admitted. This continues until the class is full. With EA, the schools want to see all the candidates applying that way and compare them to one another. Some will be admitted, some rejected, and some deferred to be compared to the ED applicants. There are probably EA schools that could fill their entire classes with qualified people who applied EA, but they want to see who will apply ED too.</p>