Q. Why are prices of factors of production not equalized?
Answer: Again this statement may not or may be argued to be true. On the other hand, the growth and large volume in world trade among the United States and other OECD countries during the 50 years since World War II has obviously been related to a near universal (average) convergence in real wage levels in these countries where the most obvious cases in which such a convergence didn't take place (North-South countries) as well happened to be cases in which trade was relatively small and "missing".
There are several theoretical reasons why factor price equalization may not take place. Stipulation the relative country relative abundances are very different, after that the theory itself doesn't predict that the wage equalization will occur. The similar is true of factor intensity reversals exist inside relevant relative wage ranges. Active migration models for instance Harris-Todaro are another class of theory that may suggest that even if the static equilibrium solution does include the factor-price equalization, the active path of the model may never reach this solution, thus that when observed within any finite time frame, it deficient in of equalization would exist.