Aren't you confusing Charles Darwin and God?
Darwin may have been right about some evolutionary process taking place, but that doesn't mean everything he said was the bible truth.
In fact, the theory of 'survival of the fittest' really doesn't hold water. If it did wolves would be more abundant than dogs. Sabre tooth tigers would rule the world. Mutts are out surviving pure breds.
Darwin lacked the knowledge of biology that we have today. Evolution seems to be based more of random genetic mutations with the most diverse gene pool evolving fastest.
Historically, the 'common' people of the world continue to proliferate, despite their apparent inability to 'compete'. While the most competitive people's genetic lines not only fail to dominate, but often cease to exist. Have you met a descendant of Julius Ceaser's lately? How about the decendants of the Kings of France or Czars of Russia?
It seems that the quality of human beings that have caused the human race to thrive are the qualities of compassion and altruism. The most competitive and aggressive people, who seem quite often to lack in genetic diversity, often end in somewhat less than 'winning' circumstances.
The meek are inheriting the earth, slowly but surely.
I believe that it will not be very long before those that have espoused 'social Darwinism' find themselves in for a big downfall.