In the 1930’s, the economist Alvin Hansen argued that opportunities for new investment in already-rich countries were drying up. Investment growth had depended on population growth, technological innovation, and westward expansion.
因此，问题在于投资前景低迷。此话怎讲？在20世纪30年代，经济学家汉森（Alvin Hanson）指出，已经致富的国家的信投资机会正在告竭。投资增长已开始依赖人口增长、技术创新和西进运动。