А может, и нет никакого эффекта?

For example, it appears that QWERTY keyboards are not inferior. Professors Stan Leibowitz and Stephen Margolis have discovered that in the 1880s and 1890s, when the typewriter business was fi rst developing, there were numerous competitive keyboards and the QWERTY board was at least as satisfactory as any of its competitors. Similarly, tests of the vaunted Dvorak keyboard showed that it had no obvious superiority over the QWERTY board. What is particularly signifi cant is that there were numerous typewriter technologies in competition in the 1880s and 1890s, and there is no reason to believe that the market selected the wrong one. S. Leibowitz and S. Margolis, ‘Policy and Path Dependence from QWERTY to Windows 95’, Regulation, vol. 18, no. 3, 1995, pp. 3ff. Available on http://www.cato.org/pubs/regulation/reg18n3d.html