Similarly a country which has leadership can lose its
hegemony and be leapfrogged by another country. This has happened in history a few times. In the late eighteenth century, the Netherlands was leapfrogged by the UK, which was the leader during the whole nineteenth century, and in turn the US leapfrogged the UK, and became the hegemonic power of the 20th century. There are several reasons for this.
Brezis and
Krugman (1993, 1997) suggest a mechanism that explains this pattern of leapfrogging as a response to occasional major changes in technology. In times of small and incremental technological change, increasing returns to scale tend to accentuate economic leadership. However, at times of a radical innovation and major technological breakthrough, economic leadership, since it also implies high wages, can deter the adoption of new ideas in the most advanced countries. A new technology may well seem initially inferior to older methods to those who have extensive experience with those older methods; yet that initially inferior technology may well have more potential for improvements and adaptation. When technological progress takes this form, economic leadership will tend to be the source of its own downfall. In consequence, when a radical innovation occurs, it does not initially seem to be an improvement for leading nations, given their extensive experience with older technologies. Lagging nations have less experience; the new technique allows them to use their lower wages to enter the market. If the new technique proves more productive than the old, leapfrogging of leadership occurs. Brezis and Krugman have applied this theory of leapfrogging to the field of geography, and explain why leading cities are often overtaken by upstart
metropolitan areas. Such upheavals may be explained if the advantage of established
urban centers rests on localized learning by doing. When a new technology is introduced, for which this accumulated experience is irrelevant, older centers prefer to stay with a technology in which they are more efficient. The changes to technological leadership can reveal the challenges concerning the effects of backwardness on the willingness to innovate or adopt radical and new ideas. New centers, however, turn to the new technology and are competitive despite the raw state of that technology because of their lower
land rents and wages. Over time, as the new technology matures, the established cities are overtaken. ==Leapfrogging in developing countries==