[dontcare007]

Think bell curve distribution and population size. That's a big difference, all other things being equal. The US just has quantitatively more individuals to the far right of the curve, just based on population size. Then cultural differences- US highly prizes individualism (or used to, at least). Japan prized homogeneity, conformance, and Zen style perfection.

[wolverine876]

Population is essential, but so are other inputs, including education. Many countries with large populations are far behind on technology. Also, you need people who are capable using technology, especially in novel ways in novel situations.