Optimal trade intensity depends on many factors – such as relative labor costs, transport costs, productivity levels, and economy-of-scale effects. Trends in these factors might make reduced trade intensity not only inevitable but desirable.
毕竟，虽然地球没有跟其他星球进行贸易，其经济却仍然保持增长。最优贸易频密度取决于许多因素——如相对劳动力成本，运输成本，生产力水平，经济规模效应。这些因素的变化趋势会令贸易频密度的降低变得不可避免，但却是有利的。