According to both popular perception and the “pioneers” of development economics studied in the previous chapters (Solow, Lewis, Rosenstein-Rodan, etc.), development is fundamentally a supply problem, not a demand issue. Somewhat brutally, in underdeveloped areas there are unemployed waiters not because people do not go to restaurants, but because the few restaurants that do exist are not sufficient to employ all those who would like to be employed. So, macroeconomic (fiscal and monetary) policies designed to stimulate spending do not serve to create what matters most, a lasting increase in the capacity to produce. In this chapter, we try to weaken this popular and dominant wisdom using a powerful reflection, and a simple formal model, proposed by A. K. Dutt (2006a). Dutt’s analysis warns us against the oversimplifications of growth models solely centered on supply factors. It teaches us not only that history matters, but also that macroeconomic policies of aggregate demand management, far from producing their effects in the “short” period alone, can instead contribute, along with other elements, to charting the long-term development path of an economy, which happens essentially because of their impact on the pace of capital accumulation and technical change. To put it as simply as possible: sometimes, increasing consumption spending (going a bit more to the restaurants) may convince private actors to invest more (open new restaurants, learning new receipts, buying newer and better machinery), which clearly expand the productive capacity of the economy in the long run. Keynes may say something in the Tropics as well.