Has all this been just coincidence?

Thomas Sowell, Random Thoughts

Those who say that all cultures are equal never explain why the results of those cultures are so grossly unequal. When some cultures have achieved much greater prosperity, better health, longer life, more advanced technology, more stable government, and greater personal safety than others, has all this been just coincidence? Moreover, people from other cultures are constantly migrating to these cultures, which fashionable dogmas say are no better than any other.