My own work has convinced me that there is no justifiable case for decreasing returns except for very short-run theory. Pigou (1927, 1928) and Nicholas Kaldor (1972, 1975) both made a strong case for universal increasing returns and Kaldor tied it to a generalized complementarity in social and economic relations, although neither really developed the most important implication, which is that cooperation, not competition, is efficient under these suppositions. Complementarity means that our interests are aligned, rather than opposed (as with the substitution case). If our relations are based on complementarity, then what emerges is a much kinder and gentler economic system based on cooperation and love (instead of being driven by fear). My questions asks us to explore what our economic culture would be like under these suppositions. That's very hard for me to imagine or project, as a "Road Not Taken" in our discipline due to our improper reliance on widespread decreasing returns assumptions.