Third, and by far the most important and least appreciated factor, closures make room for replacements, which have a transformative positive impact on the health of a field. When a firm folds due to poor performance, the slack is taken up by the expansion of successful existing firms—meaning that those excelling have the opportunity to do more—or by new firms. New entrants not only fill gaps, they have a tendency to better reflect current market conditions. They are also far likelier to introduce innovations: Google, Facebook, and Twitter were not products of long-standing firms. Certainly not all new starts will excel, not in education, not in any field. But when provided the right characteristics and environment, their potential is vast.